CREATE TABLE
On this page
Creates a new table.
As of version 7.
Syntax
CREATE [ROWSTORE] [REFERENCE | TEMPORARY | GLOBAL TEMPORARY] TABLE [IF NOT EXISTS] <table_name>(<create_definition>,...)[<table_options>][[AS] SELECT ...]CREATE TABLE [IF NOT EXISTS] new_tbl_name{ LIKE original_tbl_name | (LIKE original_tbl_name) }[WITH DEEP COPY]<create_definition>:<column_name> { <column_definition> | AS <computed_column_definition> }| [CONSTRAINT [symbol]] PRIMARY KEY [<index_type>] (<index_column_name>,...)[<index_option>] ...| { INDEX | KEY } [<index_name>] [<index_type>] (<index_col_name>,...)[<index_option>] ...| [CONSTRAINT [symbol]] UNIQUE [INDEX | KEY][<index_name>] [<index_type>] (<index_column_name>,...)[<index_option>] ...| [CONSTRAINT [symbol]] SHARD KEY [<index_type>] (<index_column_name>,...)[<index_option>] ...| SORT KEY (<index_column_name>,... [DESC])| FULLTEXT[<index_name>] (<index_column_name>,...)<column_definition>:<data_type> [NOT NULL | NULL] [DEFAULT <default_value>] [ON UPDATE <update_value>][AUTO_INCREMENT] [UNIQUE [KEY] | [PRIMARY] KEY] [SPARSE] [SERIES TIMESTAMP]<computed_column_definition>:computed_column_expression PERSISTED [data_type | AUTO]<data_type>:BIT[(<length>)]| TINYINT[(<length>)] [UNSIGNED]| SMALLINT[(<length>)] [UNSIGNED]| INT[(<length>)] [UNSIGNED]| INTEGER[(<length>)] [UNSIGNED]| BIGINT[(<length>)] [UNSIGNED]| REAL[(<length>,<decimals>)] [UNSIGNED]| DOUBLE[(<length>,<decimals>)] [UNSIGNED]| DECIMAL[(<length>[,<decimals>])] [UNSIGNED]| NUMERIC[(<length>[,<decimals>])] [UNSIGNED]| DATETIME| DATETIME(6)| TIMESTAMP| TIMESTAMP(6)| DATE| TIME| CHAR[(<length>)][CHARACTER SET <character_set_name>] [COLLATE <collation_name>]| VARCHAR(<length>)[CHARACTER SET <character_set_name>] [COLLATE <collation_name>]| TINYBLOB| BLOB| MEDIUMBLOB| LONGBLOB| TINYTEXT [BINARY]| TEXT [BINARY]| MEDIUMTEXT [BINARY]| LONGTEXT [BINARY]| ENUM(<value1>,<value2>,<value3>,...)| SET(<value1>,<value2>,<value3>,...)| JSON [COLLATE <collation_name>]| GEOGRAPHY| GEOGRAPHYPOINT<index_column_name>:<column_name> [(<length>)] [ASC | DESC]<index_type>:| USING { BTREE | HASH }<index_option>:KEY_BLOCK_SIZE [=] <value>| <index_type>| COMMENT '<string>'| BUCKET_COUNT [=] <value>| WITH (<index_kv_options>)| UNENFORCED [RELY | NORELY]<index_kv_options>:<index_kv_option> [, <index_kv_option>] ...<index_kv_option>:RESOLUTION = <value>| COLUMNSTORE_SEGMENT_ROWS = <value>| COLUMNSTORE_FLUSH_BYTES = <value><table_options>:<table_option> [[,] <table_option>] ...<table_option>:AUTO_INCREMENT [=] <value>| COMMENT [=] '<string>'| AUTOSTATS_ENABLED = { TRUE | FALSE }| AUTOSTATS_CARDINALITY_MODE = {INCREMENTAL|PERIODIC|OFF}| AUTOSTATS_HISTOGRAM_MODE = {CREATE|UPDATE|OFF}| AUTOSTATS_SAMPLING = {ON|OFF}| COMPRESSION = SPARSE
Remarks
Note
Unless CREATE ROWSTORE TABLE . or SORT KEY() are specified, the value of the default_ engine variable determines the type of table (columnstore or rowstore) that is created.
When default_ is set to columnstore, you can create a columnstore table using standard CREATE TABLE syntax.
default_ is set to columnstore by default.
The setting of default_ applies to temporary tables.GLOBAL TEMPORARY tables, if default_CREATE ROWSTORE GLOBAL TEMPORARY TABLE.GLOBAL TEMPORARY is not supported on columnstore tables.
-
For more information about the data types listed above, and for an explanation of
UNSIGNED, refer to the Data Types topic. -
The
SETdata type restricts the values that can be inserted for a table column.Only the set of strings that are listed for a column at the time of table creation can be inserted. -
<table_is the name of the table to create in the SingleStore database.name> -
The following note applies when the engine variable
table_is set toname_ case_ sensitivity OFF: After you create a table, you cannot create another table having the same table name with a different case.Refer to the Database Object Case Sensitivity topic for more information. -
CREATE TABLEis slower in SingleStore than in MySQL.See Code Generation for more information. -
The
KEYsyntax is equivalent to usingINDEXsyntax when used inCREATE TABLE.The convention is to use the KEYsyntax.INDEXsyntax is generally used when creating an index on an existing table.See CREATE INDEX for more information. -
The
BTREEindex type creates a skip list index in SingleStore.This index has very similar characteristics to a BTREE index. -
If you do not want to specify a column (or columns) to sort on, or do not care about the sort order for your data, you can specify an empty key (e.
g. SORT KEY()). -
The
SORT KEY()order can be specified as ascending (SORT KEY(index_) or descending (column_ name) SORT KEY(index_).column_ name DESC) SingleStore does not support scanning a SORT KEY()in reverse order to its sort order:CREATE TABLE ct_sort (col1 int, SORT KEY(col1 DESC));EXPLAIN SELECT * FROM ct_sort ORDER BY col1 DESC;+-------------------------------------------------------------------------------------------+ | EXPLAIN | +-------------------------------------------------------------------------------------------+ | Project [remote_0.col1] | TopSort limit:[@@SESSION.`sql_select_limit`] [remote_0.col1 DESC] | | Gather partitions:all alias:remote_0 parallelism_level:sub_partition | | Project [t1.col1] | | Top limit:[?] | | ColumnStoreFilter [<after per-thread scan begin> AND <before per-thread scan end>] | | OrderedColumnStoreScan test1.t1, SORT KEY col1 (col1 DESC) table_type:sharded_columnstore | +-------------------------------------------------------------------------------------------+EXPLAIN SELECT * FROM ct_sort ORDER BY col1;+------------------------------------------------------------------------------------+ | EXPLAIN | +------------------------------------------------------------------------------------+ | Project [remote_0.col1] | | TopSort limit:[@@SESSION.`sql_select_limit`] [remote_0.col1] | | Gather partitions:all alias:remote_0 parallelism_level:segment | | Project [t1.col1] | | TopSort limit:[?] [t1.col1] | | ColumnStoreScan test1.t1, SORT KEY col1 (col1 DESC) table_type:sharded_columnstore | +------------------------------------------------------------------------------------+ -
SORT KEY()is not allowed when usingCREATE ROWSTORE TABLE ... . -
KEY() USING CLUSTERED COLUMNSTOREis a legacy syntax that is equivalent toSORT KEY().SingleStore recommends using SORT KEY(). -
BUCKET_is specific to theCOUNT HASHindex type.It controls the bucket count of the hash table. It applies to rowstore hash indexes only and does not effect columnstore hash indexes. -
The
UNENFORCEDindex option can be used on aUNIQUEconstraint to specify that the unique constraint is unenforced.See Unenforced Unique Constraints. -
RESOLUTIONis specific to index on geospatial columns.See Working with Geospatial Features for more information. -
COLUMNSTORE_,SEGMENT_ ROWS COLUMNSTORE_controls configuration variables specific to columnstore tables.FLUSH_ BYTES See Advanced Columnstore Configuration Options) for more information. -
SingleStore supports
binary,utf8, andutf8mb4character sets.The COLLATEclause in theCREATE TABLEstatement can be used to override the server character set and collation, which are used as default values for the table.For more information, see Character Set and Collation Override.
-
AUTOSTATS_controls if automatic statistics should be collected on this table.ENABLED There are three categories of autostats - AUTOSTATS_,CARDINALITY_ MODE AUTOSTATS_, andHISTOGRAM_ MODE AUTOSTATS_.SAMPLING SingleStore allows you to independently control how each category of statistics is automatically gathered. Multiple autostats settings can be combined in a single CREATE TABLEstatement.See Automatic Statistics for more information. -
This command can be run on the master aggregator node, or a child aggregator node (see Node Requirements for SingleStore Commands ).
-
This command causes implicit commits.
Refer to COMMIT for more information. -
Specify the
AUTOoption instead of the<data_in thetype> <computed_clause to automatically infer the data type of the column from thecolumn_ definition> <computed_.column_ expression> -
<computed_defines the value of a computed column using other columns in the table, constants, built-in functions, operators, and combinations thereof.column_ expression> For more information see Persistent Computed Columns. -
Temporary tables, created with the
TEMPORARYoption, will be deleted when the client session terminates.For ODBC/JDBC, this is when the connection closes. For interactive client sessions, it is when the user terminates the client program. -
Global temporary tables, created with the
GLOBAL TEMPORARYoption, exist beyond the duration of a client session.If failover occurs, the global temporary tables lose data and enter an errored state; they need to be dropped and recreated. This command can be run only on the master aggregator. See Global Temporary Tables for details. -
The
SERIES TIMESTAMPclause specifies a table column as the default column defining time order for implicit use by time series functions.This setting can be specified only for a single table column. The column can be one of the following data types: DATE,TIME,DATETIME,DATETIME(6),TIMESTAMPorTIMESTAMP(6).SingleStore recommends to use either of the DATETIMEorDATETIME(6)types instead of one of theTIMESTAMPtypes because the automatic update behavior ofTIMESTAMPis subject to change.See Timestamp Behavior for details. -
The
SERIES TIMESTAMPclause does not affect the data type of a table column, rather it specifies the behavior of the column in the time-series-specific functions likeFIRST(),LAST(), andTIME_.BUCKET() -
Keyless sharding distributes data across partitions uniformly at random but with the limitation that it does not allow single partition queries or local joins since rows are not assigned to specific partitions.
Keyless sharding is the default for tables that do not have primary key or explicit shard key. You can explicitly declare a table as keyless sharded by specifying a shard key with an empty list of columns in the SHARD KEY()constraint in the table definition. -
Warning
For versions before 8.
1. 30/8. 0. 29, please do not use WITH DEEP COPYas it may cause permanent data loss.The
WITH DEEP COPYargument of theCREATE TABLE new_statement copies an existing table (tbl_ name LIKE original_ tbl_ name original_) and creates a new table that will have the same definition as the original table - including all of the data and metadata (such as indexes) in the original table.tbl_ name Users must have SELECTpermissions to be able to execute SQL statements against the new table.Computed columns will be recomputed during the WITH DEEP COPYprocess. -
Refer to the Permission Matrix for the required permissions.
MySQL Compatibility
SingleStore’s syntax differs from MySQL mainly in the data types and storage it supports, and some specific index hints.
-
KEY_: value is currently ignored.BLOCK_ SIZE [=] <value>
DEFAULT Behavior
If DEFAULT <default_ is specified in <column_, and no value is inserted in the column, then <default_ will be placed in the column during an INSERT operation.
ON UPDATE Behavior
If ON UPDATE <update_ is specified in <column_, and if any other column is updated but the specified column is not explicitly updated, then update_ will be placed in the column during an UPDATE operation.TIMESTAMP, TIMESTAMP(6), DATETIME , or DATETIME(6), then you can update <update_ to one of the following values: CURRENT_, CURRENT_, NOW(), or NOW(6).
ON UPDATE can be used with these TIMESTAMP/DATETIME[(6)] types only, and you can only use one of the time functions as the argument.
Storage of CHAR(<length>) as VARCHAR(<length>)
For a column defined as type CHAR of length len, store the column as a VARCHAR of length len if len greater than or equal to the value of the engine variable varchar_.0, the column is not stored as a VARCHAR.
Storing a CHAR of length len as a VARCHAR of length len will allow the column to realize the performance benefit of a VARCHAR, in many cases.
Suppose the value of varchar_ is 3 and you run:
CREATE TABLE ct_char(a CHAR(4));
The column a is stored as a VARCHAR(4).
Example(s)
CREATE TEMPORARY
CREATE TEMPORARY or CREATE ROWSTORE TEMPORARY (if default_ is set to columnstore, you must use the latter syntax) creates a table that will be deleted when the client session terminates.
CREATE TEMPORARY TABLE IF NOT EXISTS ct_temp_1 (id INT AUTO_INCREMENT PRIMARY KEY, a INT, b INT, SHARD KEY(id));CREATE ROWSTORE TEMPORARY TABLE IF NOT EXISTS ct_temp_1 (id INT AUTO_INCREMENT PRIMARY KEY, a INT, b INT, SHARD KEY(id));
CREATE ROWSTORE GLOBAL TEMPORARY
CREATE ROWSTORE GLOBAL TEMPORARY creates a table that exists beyond the duration of a client session.
CREATE ROWSTORE GLOBAL TEMPORARY TABLE IF NOT EXISTS ct_temp_2 (id INT AUTO_INCREMENT PRIMARY KEY, a INT, b INT, SHARD KEY(id));
CREATE TABLE with an AUTO_ INCREMENT Column
AUTO_ can be used to automatically generate a unique value for new rows.AUTO_ field is DEFAULT, NULL, or 0, SingleStore automatically assigns a value.AUTO_ only guarantees that automatically-generated values are unique.
-
are consecutive or sequential
-
are monotonically increasing
-
start from any particular value
-
are distinct from explicitly-set values
If you explicitly set a value in an INSERT or UPDATE statement, it may collide with past or future automatically-generated values.AUTO_ column.AGGREGATOR SYNC AUTO_ is run by the end user (which will reset the auto-increment counter to a value higher than 10).AUTO_ value reaches 10 eventually on its own as additional rows are added to the table.
CREATE TABLE ct_auto (c1 INT AUTO_INCREMENT PRIMARY KEY);INSERT INTO ct_auto (c1) VALUES (10);
A table can have only one AUTO_ column.AUTO_ column must be included in an index (not necessarily a PRIMARY or UNIQUE key, a regular key is also allowed).
If syntax such as CREATE TABLE table_ is used to create table_ where table_ has an AUTO_ column, it will be created as a non-auto-increment column in table_.
See LAST_AUTO_ behavior.
If the AUTO_ behavior described here does not satisfy your requirements you can create your own sequence generator using LAST_.
Warning
Restarting an aggregator, such as during upgrades or host machine maintenance, will introduce a large gap between any AUTO_ values inserted before the restart and any values inserted after.
These jumps are because each aggregator defines and manages its own range of values to start incrementing from to prevent collisions in a table.AUTO_ values increases to the next 1,000,000 after each restart (e.
AUTO_ INCREMENT in Sharded Tables
On a sharded (distributed) table, AUTO_ can only be used on a BIGINT column (as they usually use the entire 64 bits).AUTO_ values and uses those values when new rows are added to a table.AUTO_ values in sharded tables are assigned using the high 14 bits to encode the aggregator ID and the bottom 50 bits for a per-aggregator unique value.AUTO_ values, the automatically-generated values from inserts across multiple aggregators are only unique, never sequential.
Here is an example to illustrate how AUTO_ values are generated across aggregators in a cluster as new rows are inserted into table ct_:
SELECT * FROM ct_tb ORDER BY b;
+-------------------+------+------------+
| a | b | c |
+-------------------+------+------------+
| 1 | 1 | from MA |
| 2 | 2 | from MA |
| 3 | 3 | from MA |
| 4 | 4 | from MA |
| 5 | 5 | from MA |
| 13510798882111489 | 6 | from CA 96 |
| 13510798882111490 | 7 | from CA 96 |
| 13510798882111491 | 8 | from CA 96 |
| 13510798882111492 | 9 | from CA 96 |
| 13510798882111493 | 10 | from CA 96 |
| 14636698788954113 | 11 | from CA 20 |
| 14636698788954114 | 12 | from CA 20 |
| 14636698788954115 | 13 | from CA 20 |
| 14636698788954116 | 14 | from CA 20 |
| 14636698788954117 | 15 | from CA 20 |
| 6 | 16 | from MA |
| 15762598695796737 | 17 | from CA 17 |
| 13510798882111494 | 18 | from CA 96 |
| 7 | 19 | from MA |
| 14636698788954118 | 20 | from CA 20 |
+-------------------+------+------------+As shown in the example above, automatically-generated AUTO_ values can differ depending on which aggregator you run the inserts on.
AUTO_ INCREMENT in Reference Tables
The AUTO_ value for a reference table is tracked by the master aggregator.AUTO_ value will always be greater than any value previously seen in this column.INSERT or UPDATE statement will not create a collision with future automatically generated values.
The next example shows some queries using AUTO_ fields on reference tables.
CREATE REFERENCE TABLE ct_ref_1(id INT AUTO_INCREMENT PRIMARY KEY);INSERT INTO ct_ref_1 VALUES();INSERT INTO ct_ref_1 VALUES(5);INSERT INTO ct_ref_1 VALUES();
SELECT id FROM ct_ref_1 ORDER BY id;
+----+
| id |
+----+
| 1 |
| 5 |
| 6 |
+----+UPDATE ct_ref_1 SET id = 9 WHERE id = 5;INSERT INTO ct_ref_1();
SELECT id FROM ct_ref_1 ORDER BY id;
+----+
| id |
+----+
| 1 |
| 6 |
| 9 |
| 10 |
+----+DELETE FROM ct_ref_1;INSERT INTO ct_ref_1 VALUES();
SELECT id FROM ct_ref_1 ORDER BY id;
+----+
| id |
+----+
| 11 |
+----+Setting AUTO_ INCREMENT Starting Values
It is possible to override the starting AUTO_ value for reference tables by setting the AUTO_ option on a CREATE TABLE statement.
The following example shows how to set the AUTO_ start value during table creation:
CREATE REFERENCE TABLE ct_ref_2 (id int AUTO_INCREMENT PRIMARY KEY) AUTO_INCREMENT = 7;INSERT INTO ct_ref_2 VALUES (), ();
SELECT * FROM ct_ref_2;
+----+
| id |
+----+
| 7 |
| 8 |
+----+This syntax has no effect on sharded tables.
AUTO_ INCREMENT During Replication
When replicating data between clusters, the secondary cluster has all the replicated AUTO_ values from the primary cluster.AUTO_ values on every aggregator.
CREATE TABLE IF NOT EXISTS my_MemSQL_table (id INT PRIMARY KEY AUTO_INCREMENT, v VARCHAR(10) NOT NULL);
CREATE TABLE AS SELECT
CREATE TABLE AS SELECT (also referred to as CREATE TABLE .) can create one table from results of a SELECT query.
Here is the basic syntax.
CREATE [ROWSTORE] [REFERENCE | TEMPORARY | GLOBAL TEMPORARY] TABLE [IF NOT EXISTS] <table_name_2>(column_name(s), [SHARD KEY(column_name)] | [SORT KEY(column_name)] | [KEY(column_name)]AS SELECT [*] | [column_name(s)] FROM table_name_1;
Here is an example of a CREATE TABLE AS SELECT command with a shard key, sort key and an index:
CREATE TABLE ctas_table (a BIGINT, b BIGINT, SHARD KEY(a), SORT KEY(b), KEY(a)) AS SELECT * FROM orig_table;
The table will include a column for each column of the SELECT query.
CREATE TABLE table_1 (PRIMARY KEY (a, b)) AS SELECT * FROM table_2;CREATE TABLE table_1 (SORT KEY (a, b)) AS SELECT * FROM table_2;CREATE TABLE table_1 (a int, b int) AS SELECT c, d FROM table_2;CREATE TABLE table_1 (b AS a+1 PERSISTED int) AS SELECT a FROM table_2;
In the case that the original table (table_ in the above examples) has an AUTO_ column, it will be created as a non-auto-increment column in the new table (table_).
CREATE TABLE AS SELECT to Extract Data from One Column in an Existing Table
Extract time column from an event table to build a times table.
CREATE TABLE events (type VARCHAR(256), time TIMESTAMP);INSERT INTO events VALUES('WRITE', NOW());
CREATE TABLE times (id INT AUTO_INCREMENT KEY, time TIMESTAMP) AS SELECT time FROM events;
SELECT * FROM times;
+----+---------------------+
| id | time |
+----+---------------------+
| 1 | 2023-06-21 15:57:35 |
+----+---------------------+CREATE TABLE AS SELECT to Extract Distinct Values from an Existing Table
SELECT * FROM courses ORDER BY course_code, section_number;
+-------------+----------------+-----------------+
| course_code | section_number | number_students |
+-------------+----------------+-----------------+
| CS-101 | 1 | 20 |
| CS-101 | 2 | 16 |
| CS-101 | 3 | 22 |
| CS-101 | 4 | 25 |
| CS-101 | 5 | 22 |
| CS-150 | 1 | 10 |
| CS-150 | 2 | 16 |
| CS-150 | 3 | 11 |
| CS-150 | 4 | 17 |
| CS-150 | 5 | 9 |
| CS-201 | 1 | 14 |
| CS-201 | 2 | 17 |
| CS-301 | 1 | 7 |
| CS-301 | 2 | 10 |
+-------------+----------------+-----------------+CREATE TABLE IF NOT EXISTS distinct_courses (PRIMARY KEY(course_code))AS SELECT DISTINCT(course_code) FROM courses;
SELECT * FROM distinct_courses ORDER by course_code;
+-------------+
| course_code |
+-------------+
| CS-101 |
| CS-150 |
| CS-201 |
| CS-301 |
+-------------+CREATE TABLE USING HASH
The USING HASH clause creates a hash index in a table.
If a rowstore or columnstore table is being created, the following applies:
-
You can create single-column or multi-column hash indexes.
-
When you create a unique single-column hash index, the shard key can contain only one column, and that column must be the same column that you have created the index on.
When you create a unique multi-column hash index, the shard key must be a subset of the columns that you have created the index on. -
You can create multiple single-column hash indexes on a reference table.
If a columnstore table is being created, the following applies:
-
You can create at most one unique hash index.
You can create multiple multi-column hash indexes. -
You cannot create a unique hash index on a
FLOAT,REAL, orDOUBLEcolumn.
If a rowstore is being created, the following applies:
-
Non-unique hash indexes on rowstore tables are not supported.
-
When the
USING HASHclause is used to define a non-unique index, a skiplist index is created. -
After a table has been created, the
SHOW WARNINGScommand will display a warning that a skiplist index was created instead of a hash index. -
The
SHOW INDEXEScommand can be used to verify what types of indexes have been created.
CREATE TABLE with Multiple Hash Indexes
The following example creates a columnstore table with three hash indexes.
CREATE TABLE articles_3 (id INT UNSIGNED,month int UNSIGNED,year int UNSIGNED,title VARCHAR(200),body TEXT,SHARD KEY(title),SORT KEY (id),KEY (id) USING HASH,UNIQUE KEY (title) USING HASH,KEY (month,year) USING HASH);
The query SELECT * FROM articles WHERE title = 'Interesting title here'; uses title’s hash index since the query uses an equality predicate.
The query SELECT * FROM articles WHERE year > 2010 AND month > 5; does not use the hash index on month and year since the query does not use an equality predicate.
See the ColumnstoreFilter in the Query Plan Operations topic for an example EXPLAIN plan for a columnstore query that uses a hash index.
See Highly Selective Joins for an example of a columnstore query with a join that uses a hash index.
CREATE TABLE with One Hash Index Containing Multiple Columns
KEY(<column 1 name>,<column 2 name>, . is equivalent to KEY(<column 1 name>,<column 2 name>,..
CREATE TABLE ct_hash_1(a INT, b INT, c INT, KEY(a,b));
is equivalent to:
CREATE TABLE ct_hash_1(a INT, b INT, SORT KEY(), KEY(a,b) USING HASH);
A query against t with an equality filter on a, an equality filter on b, or equality filters on both a and b could benefit from KEY(a,b) USING HASH.
Depending on the cardinality, the performance of the query may be worse than the performance of the same query, where t is a rowstore table and KEY(a,b) is defined on that table.
CREATE TABLE with FULLTEXT Columns
SingleStore supports full-text search across text columns in a columnstore table using the FULLTEXT index type.CREATE TABLE statement and only on the text types CHAR, VARCHAR, TEXT, and LONGTEXTData Types
Warning
A FULLTEXT index cannot be dropped or altered after the table is created, and if the table is dropped, the index is deleted automatically.
If you query a column c that is part of a multi-column FULLTEXT index, where the query uses a FULLTEXT MATCH on c, the index on c will be applied.
This differs from a multi-column non-FULLTEXT index, where behavior is as follows: if you query column c that is part of index i, where the query uses an equality filter on c, the index on c will only be applied if c is the leftmost column in i.
Any column that is part of a FULLTEXT index can be queried, even if it is not the leftmost.FULLTEXT columns are done using the SELECT . syntax.
CREATE TABLE with FULLTEXT Index on Two Columns
This example creates a FULLTEXT index for both the title column and the body column.MATCH <column_, and the index on the column would be applied.
CREATE TABLE articles_1 (id INT UNSIGNED,year int UNSIGNED,title VARCHAR(200),body TEXT,SORT KEY (id),FULLTEXT (title,body));
Errors
These are the possible errors you may encounter when using FULLTEXT.
|
Error |
Error String |
|---|---|
|
Invalid Type specified for column |
Invalid type specified for |
|
Specifying |
|
|
Specifying the same column multiple times |
Column may only be specified once in a |
|
Specifying a column that is not defined on the table |
Column not defined |
|
Specifying |
Only column store tables may have a |
CREATE TABLE WITH DEEP COPY
Warning
For versions before 8.WITH DEEP COPY as it may cause permanent data loss.
The WITH DEEP COPY feature creates a new table that will have the same table definition as the original table.CREATE TABLE WITH DEEP COPY makes a full copy of the data and indexes in the original table.WITH DEEP COPY process.INSERT, UPDATE, DELETE, ALTER TABLE, or DROP TABLE) on the original table will not affect the copied table and vice versa.
The WITH DEEP COPY feature eliminates the need to run a CREATE TABLE LIKE followed by an INSERT SELECT statement.
There are some cases where WITH DEEP COPY is not supported.
Creating a rowstore deep copy of an existing table:
CREATE TABLE orig_table (a BIGINT, b BIGINT, SHARD KEY(a), SORT KEY(b));CREATE ROWSTORE TABLE ctdc_table LIKE orig_table WITH DEEP COPY;
ERROR 1706 ER_MEMSQL_FEATURE_LOCKDOWN: Feature 'CREATE Explicit ROWSTORE TABLE LIKE' is not supported by SingleStore.Creating a reference deep copy of an existing table:
CREATE TABLE orig_table (a BIGINT, b BIGINT, SHARD KEY(a), SORT KEY(b));CREATE REFERENCE TABLE ctdc_table LIKE orig_table WITH DEEP COPY;
ERROR 1706 ER_MEMSQL_FEATURE_LOCKDOWN: Feature 'CREATE REFERENCE TABLE LIKE' is not supported by SingleStore.CREATE TABLE WITH DEEP COPY Same Database
CREATE TABLE orig_table (a BIGINT, b BIGINT, SHARD KEY(a), SORT KEY(b));
INSERT INTO orig_table (a,b) VALUES (9,3), (5,2), (10,4), (12,7);
SELECT * FROM orig_table;
+----+----+
| a | b |
+----+----+
| 10 | 4 |
| 12 | 7 |
| 5 | 2 |
| 9 | 3 |
+----+----+CREATE TABLE ctdc_table LIKE orig_table WITH DEEP COPY;
SELECT * FROM ctdc_table;
+----+----+
| a | b |
+----+----+
| 10 | 4 |
| 12 | 7 |
| 5 | 2 |
| 9 | 3 |
+----+----+CREATE TABLE WITH DEEP COPY Across Databases
CREATE TABLE test1.orig_table (a BIGINT, b BIGINT, SHARD KEY(a), SORT KEY(b));
INSERT INTO test1.orig_table (a,b) VALUES (9,3), (5,2), (10,4), (12,7);
SELECT * FROM test1.orig_table;
+----+----+
| a | b |
+----+----+
| 10 | 4 |
| 12 | 7 |
| 5 | 2 |
| 9 | 3 |
+----+----+CREATE TABLE test2.ctdc_table LIKE test1.orig_table WITH DEEP COPY;
SELECT * FROM test2.ctdc_table;
+----+----+
| a | b |
+----+----+
| 10 | 4 |
| 12 | 7 |
| 5 | 2 |
| 9 | 3 |
+----+----+CREATE TABLE with COMPRESSION = SPARSE
SingleStore supports sparse data compression for rowstore tables.
Columns that use sparse data compression only store non-NULL data values.
Sparse compression has the following limitations:
-
The
SPARSEclause cannot be used for key columns.However, if a rowstore table uses sparse data compression using the COMPRESSION = SPARSEclause, then the key columns are stored in-row. -
The
SPARSEclause cannot be used for columns where the non-NULLsize of the column is greater than 15 bytes.
Refer to the Data Types topic for details.
CREATE TABLE with COMPRESSION = SPARSE All Sparse Columns
The following example demonstrates the COMPRESSION = SPARSE clause.
CREATE ROWSTORE TABLE transaction_1(id BIGINT NOT NULL,explanation VARCHAR(70),shares DECIMAL(18, 2),share_price DECIMAL(18, 2),total_amount as shares * share_price PERSISTED DECIMAL(18,2),transaction_date DATE,dividend_exdate DATE,misc_expenses DECIMAL(18, 2),country_abbreviation CHAR(6),correction_date DATE,settlement_date DATE) COMPRESSION = SPARSE;
CREATE TABLE with COMPRESSION = SPARSE Selected Sparse Columns
The following example demonstrates the SPARSE clause.
CREATE ROWSTORE TABLE transaction_2(id BIGINT NOT NULL,explanation VARCHAR(70) SPARSE,shares DECIMAL(18, 2) SPARSE,share_price DECIMAL(18, 2),total_amount as shares * share_price PERSISTED DECIMAL(18,2),transaction_date DATE,dividend_exdate DATE SPARSE,misc_expenses DECIMAL(18, 2) SPARSE,country_abbreviation CHAR(6),correction_date DATE SPARSE,settlement_date DATE SPARSE);
Listing Whether Columns use Sparse Compression
The following query lists the columns in the transaction table that was created in Example 2.
SELECT column_name, is_sparse FROM information_schema.columnsWHERE table_name = 'transaction_2';
+----------------------+-----------+
| column_name | is_sparse |
+----------------------+-----------+
| id | NO |
| explanation | YES |
| shares | YES |
| share_price | NO |
| total_amount | NO |
| transaction_date | NO |
| dividend_exdate | YES |
| misc_expenses | YES |
| country_abbreviation | NO |
| correction_date | YES |
| settlement_date | YES |
+----------------------+-----------+CREATE TABLE with COMPRESSION = SPARSE Use Case
Sparse rowstore compression works best on a wide table with more than half NULL values.NULL values in the table does not contribute to the amount of memory used.
For example, consider this wide table t having three-hundred columns:
CREATE ROWSTORE TABLE ct_sparse (c1 double,c2 double,…c300 double) COMPRESSION = SPARSE;
In SingleStore 7.t was loaded with 1.NULL.t, run the following command:
SELECT table_name, SUM(memory_use) memory_usage FROM information_schema.table_statisticsWHERE table_name = 'ct_sparse' GROUP BY table_name;
+-------------+--------------+
| table_name | memory_usage |
+-------------+--------------+
| ct_sparse | 1.23 |
+-------------+--------------+The following table lists the memory usage of table t, with and without sparse compression:
|
Compression Setting |
Memory Use |
Savings (Percent) |
|---|---|---|
|
NONE |
2. |
NA |
|
SPARSE |
1. |
53% |
For this wide table with two-thirds NULL values, you can store more than twice the data in the same amount of RAM.
Last modified: October 1, 2025