Query: select cells in column where it is not null

I am trying to pull non null data from a column. I have tried the following.

Each import range works independently.

=query({IMPORTRANGE("KEY", "Sheet!A4:A34"); IMPORTRANGE("KEY", "Sheet!A4:A34"); IMPORTRANGE("KEY", "Sheet!A4:A34"); IMPORTRANGE("KEY", "Sheet!A4:A34"); IMPORTRANGE("KEY", "Sheet!A4:A34");IMPORTRANGE("KEY", "Sheet!A4:A34"); IMPORTRANGE("KEY", "Sheet!A4:A34")}, "select Col1 where Col1 <> '' ")   =query({IMPORTRANGE("KEY", "Sheet!A4:A34"); IMPORTRANGE("KEY", "Sheet!A4:A34"); IMPORTRANGE("KEY", "Sheet!A4:A34"); IMPORTRANGE("KEY", "Sheet!A4:A34"); IMPORTRANGE("KEY", "Sheet!A4:A34");IMPORTRANGE("KEY", "Sheet!A4:A34"); IMPORTRANGE("KEY", "Sheet!A4:A34")}, "select A where B is not null")