Support to compare tuples in (equal) operator(s)

[seut]

Problem Statement

Currently, CrateDB's comparison operators do not support to compare tuples.
Following query doesn't work:

SELECT 1 WHERE (1,2) = (1,2)

Possible Solutions

Comparing tuples with (equal) operator(s) is supported.

Considered Alternatives

This can be of course done by comparing each tuple value dedicated combined by an AND operator:

SELECT 1 WHERE 1 = 1 AND 2 = 2

But when considering the usage inside a sub-query for example like this:

SELECT 1 
FROM t1 a
WHERE (a.x, a.y) IN (
    SELECT
      b.x,
      b.y
    FROM t1 b
)

the only workaround is to:

a) repeat the sub-query in each comparison which may result in poor performance due to repeated execution (depends on the internal optimizer/implementation)

SELECT 1 
FROM t1 a
WHERE 
  a.x IN (
    SELECT
      b.x
    FROM t1 b
  )
  AND
  a.y IN (
    SELECT
      b.y
    FROM t1 b
  )

b) or re-using a CTE which may not result in repeated execution but may not be comfortable to use

WITH c(x, y) AS (
    SELECT
      b.x,
      b.y
    FROM t1 b
)
SELECT 1 
FROM t1 a
WHERE 
  a.x IN (SELECT x FROM c)
  AND 
  a.y IN (SELECT y FROM c)