inline source-column's value instead of selecting it as a column

[myguidingstar]

this is only relevant to a join child:

SELECT foo.col AS `foo/col`, foo.id AS `foo/id` FROM foo WHERE foo.id = ?
1

vs

SELECT foo.col AS `foo/col`, 1 AS `foo/id` FROM foo WHERE foo.id = ?
1

[myguidingstar]

this can be helpful for aggregate pseudo columns so they won't need to specify GROUP BY