Warning
SingleStore 9.0 gives you the opportunity to preview, evaluate, and provide feedback on new and upcoming features prior to their general availability. In the interim, SingleStore 8.9 is recommended for production workloads, which can later be upgraded to SingleStore 9.0.
SUBSTRING
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Extracts a range of characters from a string.
Syntax
SUBSTRING(str, start, len)SUBSTR(str, start, len)SUBSTRING(str, start)SUBSTR(str, start)SUBSTRING(str FROM start FOR len)SUBSTR(str FROM start FOR len)SUBSTRING(str FROM start)SUBSTR(str FROM start)
Arguments
-
str: any string or binary object
-
start: the one-indexed position to start at.
If negative, counts from the end. -
len: length is the number of characters to extract.
Forms without len, extract characters until the end of the string.
Return Type
String
Remarks
-
In
SUBSTRorSUBSTRING, the starting index point of a string is1(0is an alias for1).
Examples
In the following example, the starting index 3 represents the third character in the string, because the index starts from 1.
SELECT SUBSTRING('1234567890', 3, 3);
+-------------------------------+
| SUBSTRING('1234567890', 3, 3) |
+-------------------------------+
| 345 |
+-------------------------------+In the following example, the substring is returned from the end, because the starting index is a negative number.
SELECT SUBSTRING('1234567890', -3, 3);
+--------------------------------+
| SUBSTRING('1234567890', -3, 3) |
+--------------------------------+
| 890 |
+--------------------------------+The following examples demonstrate how substring works using different lengths and starting positions.
CREATE TABLE sub_tab(a INT, b INT, c INT, d INT);INSERT INTO sub_tab VALUES(1234,1234,1234,1234),(1,2,4, NULL);
SELECT substr(a,0,1) FROM sub_tab;
+---------------+
| substr(a,0,1) |
+---------------+
| 1 |
| 1 |
+---------------+SELECT substr(a,1,1) FROM sub_tab;
+---------------+
| substr(a,1,1) |
+---------------+
| 1 |
| 1 |
+---------------+SELECT substr(a,1,2) FROM sub_tab;
+---------------+
| substr(a,1,2) |
+---------------+
| 1 |
| 12 |
+---------------+SELECT substr(a,0,2) FROM sub_tab;
+---------------+
| substr(a,0,2) |
+---------------+
| 12 |
| 1 |
+---------------+Caution
Implicit Collation
When character_ is set to utf8, string literals with characters using 4-byte encoding are implicitly assigned binary collation and processed as a sequence of bytes rather than characters.utf8mb4 character set.
For more information, refer to Implicit Collation in Special Cases.
Related Topics
Last modified: June 12, 2023