P (Population/Problem)

I (Intervention)

C (Comparison/Control)

O (Outcome)

Too many ( in query. Or not enough ) in query.

Too many ) in query. Or not enough ( in query.

Too many [ in query. Or not enough ] in query.

Too many ] in query. Or not enough [] in query.

Incorrect number of quote signs.

Semantically potentially unclear boolean operator(s).