STD
On this page
Calculates the population standard deviation value from a set of numbers.
STD has synonyms STDDEV and STDDEV_ which are equivalent.
May be used as a window function.
Syntax
STD returns NULL if there are not matching rows.
Aggregate Function
STD ( expression )
Window Function
STD (col | expr ) OVER ( [PARTITION BY (col | expr )] [ORDER BY (col | expr ) ] )
Arguments
-
expression: any expression.
This may be a column name, the result of another function, or a math operation.
Return Type
A double.
Examples
CREATE TABLE player_scores(player_name VARCHAR(50), player_id VARCHAR(10),1st_qtr_score DECIMAL(5,2), 2nd_qtr_score DECIMAL(5,2),3rd_qtr_score DECIMAL(5,2), 4th_qtr_score DECIMAL(5,2),yearly_total AS 1st_qtr_score + 2nd_qtr_score + 3rd_qtr_score + 4th_qtr_score PERSISTED DECIMAL(5,2));INSERT INTO player_scores VALUES('Steve', '119','22.50','72.00', '63.00', '45.00'),('Jack', '432', '90.10', '78.00','88.20', '92.20'),('Jim', '779','75.00', '68.90','55.70', '72.00'),('Eve', '189','91.50', '88.10', '95.00', '94.50'),('Shelia','338', '75.60', '72.00', '81.10', '78.40'),('June', '521', '81.00', '87.30','76.80','82.20'),('Martin', '674','98.80', '95.10', '88.00', '96.40');
Aggregate Function
SELECT STD(yearly_total) FROM player_scores;
+-------------------+
| STD(yearly_total) |
+-------------------+
| 57.083158 |
+-------------------+Window Function
SELECT player_name, yearly_total,ROUND(std(yearly_total) OVER (ORDER BY player_name, yearly_total)) as stdFROM player_scoresORDER BY player_name;
+-------------+--------------+------+
| player_name | yearly_total | std |
+-------------+--------------+------+
| Eve | 369.10 | 0 |
| Jack | 348.50 | 10 |
| Jim | 271.60 | 42 |
| June | 327.30 | 36 |
| Martin | 378.30 | 38 |
| Shelia | 307.10 | 37 |
| Steve | 202.50 | 57 |
+-------------+--------------+------+Last modified: September 6, 2024