clickhouse : left join using IN - left-join

Question

I wish to perform a left join based on two conditions :
SELECT
...
FROM
sometable AS a
LEFT JOIN someothertable AS b ON a.some_id = b.some_id
AND b.other_id IN (1, 2, 3, 4)
I got the error:
Supported syntax: JOIN ON Expr([table.]column, ...) = Expr([table.]column, ...) [AND Expr([table.]column, ...) = Expr([table.]column, ...) ...]```
It seems that the condition for a join must be = and can't be in
Any idea ?

Answer 1

Consider moving IN-operator into subquery:
SELECT
a.number,
b.number
FROM numbers(8) AS a
LEFT JOIN
(
SELECT *
FROM numbers(234)
WHERE number IN (1, 2, 3, 4)
) AS b USING (number)
/*
┌─number─┬─b.number─┐
│ 0 │ 0 │
│ 1 │ 1 │
│ 2 │ 2 │
│ 3 │ 3 │
│ 4 │ 4 │
│ 5 │ 0 │
│ 6 │ 0 │
│ 7 │ 0 │
└────────┴──────────┘
*/
or
SELECT
a.number,
b.number
FROM numbers(8) AS a
LEFT JOIN
(
SELECT *
FROM numbers(234)
WHERE number IN (1, 2, 3, 4)
) AS b USING (number)
SETTINGS join_use_nulls = 1 /* 1 is 'JOIN behaves the same way as in standard SQL. The type of the corresponding field is converted to Nullable, and empty cells are filled with NULL.' */
/*
┌─number─┬─b.number─┐
│ 0 │ ᴺᵁᴸᴸ │
│ 1 │ 1 │
│ 2 │ 2 │
│ 3 │ 3 │
│ 4 │ 4 │
│ 5 │ ᴺᵁᴸᴸ │
│ 6 │ ᴺᵁᴸᴸ │
│ 7 │ ᴺᵁᴸᴸ │
└────────┴──────────┘
*/