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Version: 3.2

variance,var_pop,variance_pop

Description​

Returns the population variance of an expression. Since v2.5.10, this function can also be used as a window function.

Syntax​

VARIANCE(expr)

Parameters​

expr: the expression. If it is a table column, it must evaluate to TINYINT, SMALLINT, INT, BIGINT, LARGEINT, FLOAT, DOUBLE, or DECIMAL.

Return value​

Returns a DOUBLE value.

Examples​

MySQL > select var_pop(i_current_price), i_rec_start_date from item group by i_rec_start_date;
+--------------------------+------------------+
| var_pop(i_current_price) | i_rec_start_date |
+--------------------------+------------------+
|       314.96177792808226 | 1997-10-27       |
|       463.73633459357285 | NULL             |
|       302.02102643609123 | 1999-10-28       |
|        337.9318386924913 | 2000-10-27       |
|       333.80931439318346 | 2001-10-27       |
+--------------------------+------------------+

MySQL > select variance(i_current_price), i_rec_start_date from item group by i_rec_start_date;
+---------------------------+------------------+
| variance(i_current_price) | i_rec_start_date |
+---------------------------+------------------+
|        314.96177792808226 | 1997-10-27       |
|         463.7363345935729 | NULL             |
|        302.02102643609123 | 1999-10-28       |
|         337.9318386924912 | 2000-10-27       |
|        333.80931439318346 | 2001-10-27       |
+---------------------------+------------------+

keyword​

VARIANCE,VAR_POP,VARIANCE_POP