有以下表格:
Thingie | Value
--------+-------
Thing1 | 10
Thing1 | 15
Thing1 | 16
在MySQL中可以这样做:
SET @halfvalue := 0;
SELECT Thingie, Value,
(@halfvalue := Value / 2) AS HalfValue,
(@halfvalue / 2) AS HalfOfHalf
FROM Things
输出
Thingie | Value | HalfValue | HalfofHalf
--------+-------+-----------+------------
Thing1 | 10 | 5.00 | 2.50
Thing1 | 15 | 7.50 | 3.75
Thing1 | 16 | 8.00 | 4.00
有什么解决办法吗?
发布于 2018-07-26 13:39:19
可以分两步完成:
DECLARE @halfvalue FLOAT = 0;
SELECT Thingie
, [Value]
, HalfValue = [Value]/2
, @halfvalue = ([Value] / 2)
FROM Things ;
SELECT Thingie
, [Value]
, HalfValue = [Value]/2
, HalfAgainValue = @halfvalue / 2
FROM Things ;
https://stackoverflow.com/questions/-100008716
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