COUNT_IF
COUNT_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.
COUNT_IF(column, cond)
Examples
tip
numbers_mt(N) – A table for test with the single number
column (UInt64) that contains integers from 0 to N-1.
SELECT count(number) FROM numbers(10);
+---------------+
| count(number) |
+---------------+
| 10 |
+---------------+
SELECT count_if(number, number > 7) FROM numbers(10);
+--------------------------------+
| count_if(number, (number > 7)) |
+--------------------------------+
| 2 |
+--------------------------------+