Google sheets query multi conditional date cell ref [duplicate]

Question

I have a doubt regarding a change in this formulas in sheets:

=INDEX(QUERY($A$3:$H; "SELECT sum (D) where C='Pub'");2)

=INDEX(QUERY($A$3:$K; "SELECT sum (F) where C='Reg'and K='"& K15&"'");0)

Formula number 1 works fine, but when I add 'and' to it (formula 2), I cannot use "2" as index value, and when I use 0 or 1 the result shown in the cell is "Sum"....(k15 cell is a date: 31/01/2018)

Any clue why this could happen?

Answer 1

INDEX use 1 based indexes, meaning that the indexes start on 1. By the other hand to make QUERY return no column headers use use the clause label to set the column label to empty strings. Example:

=INDEX(QUERY($A$3:$K; "SELECT sum (F) where C='Reg'and K='"& K15&"' label sum (F) ''");0)