[functions] Conditional Functions

[BohuTANG]

Summary

If
Controls conditional branching. Unlike most systems, ClickHouse always evaluate both expressions then and else.
Syntax:

SELECT if(cond, then, else)

Example:

Query:

SELECT if(1, 2+2, 2+6);

Result:

┌─plus(2, 2)─┐
│          4 │
└────────────┘

Query:

SELECT if(0, 2+2, 2+6);

Result:

┌─plus(2, 6)─┐
│          8 │
└────────────┘

Reference:
https://clickhouse.tech/docs/en/sql-reference/functions/conditional-functions/#if

[zhaox1n]

/assignme

[zhyass]

/assignme