AVG_IF
AVG_IF
The suffix -If can be appended to the name of any aggregate function. In this case, the aggregate function accepts an extra argument – a condition.
AVG_IF(column, cond)
Examples
tip
numbers(N) – A table for test with the single number
column (UInt64) that contains integers from 0 to N-1.
mysql> SELECT avg(number) FROM numbers(10);
+-------------+
| avg(number) |
+-------------+
| 4.5 |
+-------------+
mysql> SELECT avgIf(number, number > 7) FROM numbers(10);
+-----------------------------+
| avgIf(number, (number > 7)) |
+-----------------------------+
| 8.5 |
+-----------------------------+