MySQL中实现插入或更新操作（类似Oracle的merge语句

INSERT INTO tbl (columnA,columnB,columnC) VALUES (1,2,3) ON DUPLICATE KEY UPDATE columnA=IF(columnB>0,1,columnA)

INSERT INTO tbl (columnA,columnB,columnC) VALUES (1,2,3) ON DUPLICATE KEY UPDATE columnA=IF(columnB>0,1,columnA)，columnB=IF(columnC>0,1,columnB),columnC=IF(columnA>0,1,columnC);