Is there any performance gain by the interpreter of the query is I specify the table on a join and make the cast explicit?

Instead of

join table_join on field1_from = field1_join and field2_join = '2'


join table_join on table_from.field1_from = table_join.field1_join and table_join.field2_join::text = '2'::text

It seems that this should make the job of the parser a little easier

  • 1
    What data type is field2_join? If that is a number you shouldn't compare it to a string. But in general, to find out if two queries are in the same way, check the execution plan generated using explain (analyze, verbose, buffers) to Sep 3 '18 at 18:33

It is a good practice to use aliases to qualify tables etc

Select a.c1, b.c2
From table1 as a

However, that has very little to do with performance. Identifying each table etc is only a fraction of what the optimizer does and I would be surprised if it even is noticeable.

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