Question

我正在尝试创建一个输出20行的Oracle查询。每行（name_x）只能在col_a1和col_a2之外具有一个值。每次我运行下面的查询时，我只会得到1行。和'name_1'到'name_20'的结果为零，但Name_T已成功发布。

SELECT col_a1, col_a2, 
Coalesce (max(name_1),0) name_1,
Coalesce (max(name_2),0) name_2,
Name_t
...

FROM(
SELECT 
CASE WHEN b.col_b1 = 'Y' and a.col_a3 = 'X' THEN a.col_a4 ELSE NULL END name_1,
CASE WHEN b.col_b1 = 'Y' and a.col_a3 = 'X2' THEN a.col_a4 ELSE NULL END name_2,
…
CASE WHEN a.col_A3 = 'Z' then a.col_a4 else null name_T
FROM dbA.TbA a  
LEFT OUTER JOIN (SELECT * FROM dbB.TbB Where X) b
ON a.col_W = b.col_W
)
Group by col_a1, col_a2

好吧，在阅读评论之后，我回过头来修复了由于我的子查询无法正常工作而导致的一些错误。我能够第一次正确发布子查询！现在，我无法“通过col_a1，col_a2进行分组”并获得无效的标识符错误，该错误现在正在处理。

Answer 1

我认为，您忘记在子查询中添加col_a1, col_a2。

SELECT col_a1, col_a2, 
Coalesce (max(name_1),0) name_1,
Coalesce (max(name_2),0) name_2,
Name_t
...

FROM(
SELECT 
col_a1, col_a2,
CASE WHEN b.col_b1 = 'Y' and a.col_a3 = 'X' THEN a.col_a4 ELSE NULL END name_1,
CASE WHEN b.col_b1 = 'Y' and a.col_a3 = 'X2' THEN a.col_a4 ELSE NULL END name_2,
…
CASE WHEN a.col_A3 = 'Z' then a.col_a4 else null name_T
FROM dbA.TbA a  
LEFT OUTER JOIN (SELECT * FROM dbB.TbB Where X) b
ON a.col_W = b.col_W
)
Group by col_a1, col_a2

多个CASE WHEN语句仅输出单行

1 个答案: