USE IF FOR EXTERNAL USE IN MSSQL

Question

I want to write an IF condition in EXTERNAL APPLICATION . I need to return more than one column, so I don't want to write subqueries

SELECT name FROM v_users OUTER APPLY ( IF CAST(reg_date AS DATE)<CAST('03/25/2017' AS DATE) SELECT gender,email,age,class FROM tb_register_old WHERE id=v_users.user_id; ELSE SELECT gender,email,age,class FROM tb_register_new WHERE id=v_users.user_id; )s 

Answer 1

Maybe this?

 SELECT name FROM v_users OUTER APPLY ( SELECT gender,email,age,class FROM tb_register_old WHERE id=v_users.user_id and CAST(reg_date AS DATE)<CAST('03/25/2017' AS DATE) UNION ALL SELECT gender,email,age,class FROM tb_register_new WHERE id=v_users.user_id and CAST(reg_date AS DATE) >= CAST('03/25/2017' AS DATE) )s