如果5大于2，我想选择*，如果为假，则选择特定列。我哪里错了？SELECTIF(5>2,*,column_x),CASEwhereheard_nameWHEN'Newspaper'THEN'a'WHEN'TV'THEN'b'WHEN'Internet'THEN'c'ELSE'-'ENDASresultFROMwhereheard;感谢您对上述问题的回答。这是我正在使用的以下示例存储过程:DELIMITER$$USE`registration`$$DROPPROCEDUREIFEXISTS`test2`$$CREATEDEFINER=`root`@`localhost`PROCEDURE