在T-SQL中分解2列以上的表

Question

如果我有下表

Hour    Clicks  Conversions
12:00   2   0
1:00    3   2
2:00    1   1

我如何编写一个SELECT语句,在两列中分解它,所以我得到:

12:00   1   0
12:00   1   0
1:00    1   0
1:00    1   1
1:00    1   1
2:00    1   1

如果我不能用SELECT做到这一点,我如何用循环编写存储过程？

谢谢!

Answer 1

这假设任何给定值都只有一行[Hour].如果可能有重复,我会首先聚合(我假设源已经是某种聚合).

DECLARE @x TABLE ([Hour] CHAR(5), Clicks INT, Conversions INT);

INSERT @x SELECT '12:00',2,0
UNION ALL SELECT '13:00',3,2
UNION ALL SELECT '14:00',1,1;

;WITH x AS
(
    SELECT n = ROW_NUMBER() OVER (ORDER BY s1.[object_id]) FROM sys.all_columns AS s1
    -- CROSS JOIN (SELECT 1 UNION ALL SELECT 2) AS s2 -- to double the rows if you need more
),
y AS 
(
    SELECT [Hour], Conversions, Clicks, 
    m = MAX(CASE WHEN Conversions > Clicks THEN Conversions ELSE Clicks END) 
    FROM @x GROUP BY [Hour], Conversions, Clicks
)
SELECT y.[Hour],
    Clicks = CASE WHEN Clicks < x.n THEN 0 ELSE 1 END,
    Conversions = CASE WHEN Conversions < x.n THEN 0 ELSE 1 END
FROM x INNER JOIN y ON x.n <= y.m
ORDER BY CONVERT(TIME, y.[Hour]), Clicks, Conversions;