1
SELECT
SUM (
CASE
WHEN pop.usertype=1 THEN pop.useramount
WHEN pop.usertype=2 THEN 0-pop.useramount
END)
FROM
popular pop
;
如何將此語句轉換爲DECODE函數?在Oracle SQL中將CASE函數更改爲DECODE函數
我已經試過這(和其他輕微的變化) - 但我似乎總是得到不同的結果..
SELECT
SUM (
DECODE(pop.usertype,'1', 'pop.useramount',
'2', '0-pop.useramount')
)
FROM
popular pop
;
我試圖理解DECODE函數更好,但我真的很困惑爲什麼這不起作用?