如何使用此SQL语句执行左侧子查询或子查询？

Question

我有几个AA和left join，所以我想补充/合并这sql我的其他查询中：

SELECT 
    A.ID 
FROM 
    Table1 as A 
LEFT JOIN 
    (SELECT 
     T.ID, T.TRF_TAKEN, 
     SUM(CASE WHEN CAST([UNT_TRNSFER] AS FLOAT) = 0 
        THEN CAST([TRF_TAKEN] AS FLOAT) 
        ELSE ISNULL([UNT_TRNSFER], 0) 
      END) AS 'UNT_TRNSFER' 
    FROM TRNS_C as T 
    GROUP BY ID;) ON A.ID = TransfC.ID 
WHERE 
    A.ID = 1; 

ERROR

列“TRNS_C.TRF_TAKEN”在选择列表中，因为无效它不包含在聚合函数或GROUP BY子句中。

Answer 1

从GROUP BY ID;)删除;，加T.TRF_TAKEN到GROUP BY条款并添加表的别名Transfc，你加入了。

SELECT A.ID, Transfc.UNT_TRNSFER 
FROM Table1 AS A 
LEFT JOIN (
    SELECT T.ID, T.TRF_TAKEN, 
      SUM(CASE WHEN CAST([UNT_TRNSFER] AS FLOAT) = 0 THEN CAST([TRF_TAKEN] AS FLOAT) 
      ELSE ISNULL([UNT_TRNSFER], 0) END) AS 'UNT_TRNSFER' 
      FROM TRNS_C as T 
      GROUP BY T.ID, T.TRF_TAKEN 
) Transfc 
ON A.ID = TransfC.ID 
WHERE A.ID = 1; 

Answer 2

你只需要把你的非聚合字段放到GROUP BY中。您正在要求它按EMPLID进行分组，但您只选择了t.ID和t.TRF_Taken。

select A.ID 
from Table1 as A 

LEFT JOIN (
    SELECT T.ID, T.TRF_TAKEN, 
      SUM(CASE WHEN CAST([UNT_TRNSFER] AS FLOAT) = 0 THEN CAST([TRF_TAKEN] AS FLOAT) ELSE ISNULL([UNT_TRNSFER], 0) END) AS 'UNT_TRNSFER' 
      FROM TRNS_C as T 
      GROUP BY T.ID, T.TRF_TAKEN; 
    ) Transfc 
ON A.ID = TransfC.ID 
    Where A.ID = 1; 

Answer 3

作为一个说明，在你的问题查询大约相当于：

SELECT A.ID 
FROM Table1 A 
WHERE A.ID = 1; 

您left join可能做的是乘以行数的唯一的事情。这似乎不太可取。