Preventing integer division by casting one of the operands as non-integer

Question

Do I have to cast both the numerator and the denominator to a non-integer data type to prevent integer division?

Honestly how hard would that have been to test? `select 1/2::numeric ; 0.50000000000000000000` — Adrian Klaver, Feb 06 '23 at 18:14
@AdrianKlaver It is *very* easy to test. All the more surprising is that some upvoted answers that I listed under **"SEE ALSO"** section have one extra cast (e.g., 2 casts, when 1 cast is enough). This extra cast is confusing and not needed. — Timur Shtatland, Feb 06 '23 at 18:19

Timur Shtatland · Accepted Answer · 2023-02-06T19:21:34.390

It is enough to cast one of the operands (either the numerator or the denominator) to prevent integer division, as the manual says. Casting both is not necessary:

select 2 / 4;                      -- 0
select 2::numeric / 4;             -- 0.50000000000000000000
select 2 / 4::numeric;             -- 0.50000000000000000000
select 2::numeric / 4::numeric;    -- 0.50000000000000000000

SEE ALSO:

These have 2 casts, while only 1 cast is needed:

Preventing integer division by casting one of the operands as non-integer

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