Alias option in SQL Query -

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select b.test_id,d.test_id test b, test d

what result on stated query. either both columns result same 1 or different?

you have cartesian product a.k.a cross join of rows.

the cross join not apply predicate filter records joined table.

for rows 1, 2, , 3 in test this:

1,1 1,2 1,3 2,1 2,2 2,3 3,1 3,2 3,3

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