mysql sum 判断_mysql sum中加条件判断，性能哪个更好？

SELECT

SUM(

IF(

MONTH(B.CREATE_TIME)= '01',

B.GOODS_NUM,

0

)

),

SUM(

IF(

MONTH(B.CREATE_TIME)= '02',

B.GOODS_NUM,

0

)

),

SUM(

IF(

MONTH(B.CREATE_TIME)= '03',

B.GOODS_NUM,

0

)

),

SUM(

IF(

MONTH(B.CREATE_TIME)= '04',

B.GOODS_NUM,

0

)

),

SUM(

IF(

MONTH(B.CREATE_TIME)= '05',

B.GOODS_NUM,

0

)

),

SUM(

IF(

MONTH(B.CREATE_TIME)= '06',

B.GOODS_NUM,

0

)

),

SUM(

IF(

MONTH(B.CREATE_TIME)= '07',

B.GOODS_NUM,

0

)

),

SUM(

IF(

MONTH(B.CREATE_TIME)= '08',

B.GOODS_NUM,

0

)

),

SUM(

IF(

MONTH(B.CREATE_TIME)= '09',

B.GOODS_NUM,

0

)

),

SUM(

IF(

MONTH(B.CREATE_TIME)= '10',

B.GOODS_NUM,

0

)

),

SUM(

IF(

MONTH(B.CREATE_TIME)= '11',

B.GOODS_NUM,

0

)

),

SUM(

IF(

MONTH(B.CREATE_TIME)= '12',

B.GOODS_NUM,

0

)

)

FROM

order_goods AS B

WHERE

YEAR(B.CREATE_TIME)= '2015' GROUP BY

B.GOODS_ID

--------------------------------------------------------

SELECT

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "01" THEN

B.GOODS_NUM

ELSE

0

END

),

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "02" THEN

B.GOODS_NUM

ELSE

0

END

),

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "03" THEN

B.GOODS_NUM

ELSE

0

END

),

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "04" THEN

B.GOODS_NUM

ELSE

0

END

),

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "05" THEN

B.GOODS_NUM

ELSE

0

END

),

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "06" THEN

B.GOODS_NUM

ELSE

0

END

),

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "07" THEN

B.GOODS_NUM

ELSE

0

END

),

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "08" THEN

B.GOODS_NUM

ELSE

0

END

),

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "09" THEN

B.GOODS_NUM

ELSE

0

END

),

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "10" THEN

B.GOODS_NUM

ELSE

0

END

),

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "11" THEN

B.GOODS_NUM

ELSE

0

END

),

SUM(

CASE

WHEN MONTH(B.CREATE_TIME)= "12" THEN

B.GOODS_NUM

ELSE

0

END

)

FROM

order_goods B

WHERE

YEAR(B.CREATE_TIME)= "2015"

GROUP BY

B.GOODS_ID