Re: PostgreSQL 9.5 operator precedence

On Mon, Sep 19, 2016 at 11:02 PM, Андрей Авакимов <aquarius1993(at)rambler(dot)ru>
wrote:

> Hello,
> I've got a question about operator precedence is version 9.5
>
> Versions lower than 9.5 worked well with constructions like
> select a is null = b is null
> (it calculates if a is null, then if b is null and then compare two
> booleans)
>
> But now everything is changed, and official 9.5 documentations says that
> IS operator has lower precedence than = operator
>
> The thing I don't understand is the error message that I receive:
>
> select 1 is null = 2 is null;
> -----------------------------
> ERROR: operator does not exist: boolean = integer
> LINE 1: select 1 is null = 2 is null
> ^
> HINT: No operator matches the given name and argument type(s). You
> might need to add explicit type casts.
>
​Your query reads:

SELECT ( ( 1 IS (NULL = 2) ) IS NULL​

​)

So the error is in:

1 IS (NULL = 2)

which indeed is integer = boolean

David J.
​