While there's no IN in google sheets unlike in SQL, I'm not looking for several strings in one column. I'm looking for one string in several columns.
So what's the shortcut of
=QUERY($A:$K, "select A where B contains '"&N1&"' or C contains '"&N1&"' or D contains'"&N1&"' or E contains '"&N1&"' or F contains '"&N1&"' or G contains '"&N1&"' or H contains '"&N1&"' or I contains '"&N1&"' or J contains '"&N1&"' or K contains '"&N1&"'",3)
?
I'm hoping for something like
=QUERY($A:$K, "select A where B,C,D,E,F,G,H,I,J,K contains '"&N1&"'",3)
OK two ways you might try
An array formula which tots up the number of matches in each row
=query({A:A,arrayformula(mmult(n(isnumber(find(N1,B:K))),transpose(column(B:K))^0))},"select Col1 where Col2>0")
or a hacky way which is like the workaround for a join in the reference in your question
=query(A:K,"select A where B contains '"&N1&"'" & arrayformula(concatenate(" or "&char(column(C:K)+64)& " contains '"&N1&"'")))
(works for single-letter column references only but may be quicker than the first one).