drop procedure if exists p_hello_world; create procedure p_hello_world(in v_id int) begin if (v_id > 0) then select ‘> 0‘; elseif (v_id = 0) then select ‘= 0‘; else select ‘< 0‘; end if; end; call p_hello_world(-9);
MySQL PLSQL Demo - 005.IF THEN ELSEIF THEN ELSE END IF
原文：http://www.cnblogs.com/nick-huang/p/4626521.html