You cannot run a SELECT using RUNSQLSTM.
SELECT is not allowed in RUNSQLSTM simply because it’s meaningless. Once selected, there is no facility in RUNSQLSTM actually to do anything with the selected rows and columns. If a SELECT is intended, then it must be embedded in some program that can perform the necessary I/O to do what’s needed with that selected set.
STRQMQRY provides a means of displaying or printing the selected set or copying them to another file.
RUNSQLSTM is for SQL statements that can perform actions in themselves — e.g., INSERT, UPDATE, CREATE PROCEDURE, etc.