基于SQL Server中其他表中的值更新多列

我需要根据“引用”表中的值更新“主”表中的多个列。 例如，在给定的示例数据中，@MAIN_表应该根据连接条件（MAIN.ID_1=ref.ID_1和MAIN.ID_2=ref.ID_2）和字段ref.FLD_NAME的值更新为第一条记录（ID_1=10，ID_2=100）的ABC_VAL=11111，KLM_VAL=33333，XYZ_VAL=2222。即，如果ref.FLD_NAME='ABC'，main.ABC_VAL应使用相应的ref.FLD_VAL更新

DECLARE @MAIN_TABLE TABLE ([ID_1] INT, [ID_2] INT, [ABC_VAL] INT, [KLM_VAL] INT, [XYZ_VAL] INT) 
insert @MAIN_TABLE values
(10,100,NULL,NULL,NULL),
(10,200,NULL,NULL,NULL),
(30,300,NULL,NULL,NULL)


DECLARE @REF_TABLE TABLE ([ID_1] INT, [ID_2] INT, [FLD_NAME] varchar(3),[FLD_VAL] INT) 
insert @REF_TABLE values
(10,100,'ABC',11111),
(10,100,'XYZ',22222),
(10,100,'KLM',33333),
(20,200,'ABC',88888),
(30,300,'KLM',55555)

---

当表达式

update m set ABC_VAL = abc, XYZ_VAL = xyz, KLM_VAL = klm
from @MAIN_TABLE m
join
(
  select id_1, id_2, min(case when fld_name = 'ABC' then fld_val end) as abc,
    min(case when fld_name = 'XYZ' then fld_val end) as xyz,
    min(case when fld_name = 'KLM' then fld_val end) as klm,
  from @REF_TABLE
  group by id_1, id_2, fld_name
) A on m.id_1 = a.id_1 and m.id_2 = a.id_2

---

您可以使用以下脚本使用所需的结果更新列-

DECLARE @MAIN_TABLE TABLE ([ID_1] INT, [ID_2] INT, [ABC_VAL] INT, [KLM_VAL] INT, [XYZ_VAL] INT) 
insert @MAIN_TABLE values
(10,100,NULL,NULL,NULL),
(10,200,NULL,NULL,NULL),
(30,300,NULL,NULL,NULL)


DECLARE @REF_TABLE TABLE ([ID_1] INT, [ID_2] INT, [FLD_NAME] varchar(3),[FLD_VAL] INT) 
insert @REF_TABLE values
(10,100,'ABC',11111),
(10,100,'XYZ',22222),
(10,100,'KLM',33333),
(20,200,'ABC',88888),
(30,300,'KLM',55555)

SELECT * FROM @MAIN_TABLE
SELECT * FROM @REF_TABLE

UPDATE MT
SET MT.ABC_VAL = B.ABC_VAL,
MT.XYZ_VAL = B.XYZ_VAL,
MT.KLM_VAL = B.KLM_VAL
FROM @MAIN_TABLE MT
INNER JOIN (
    SELECT A.ID_1,A.ID_2,
    SUM(A.ABC_FLD_VAL) AS [ABC_VAL],
    SUM(A.XYZ_FLD_VAL) AS [XYZ_VAL],
    SUM(A.KLM_FLD_VAL) AS [KLM_VAL]
    FROM (
        SELECT DISTINCT MT.ID_1,MT.ID_2,
        CASE WHEN rt.FLD_NAME = 'ABC' THEN FLD_VAL  ELSE NULL END 'ABC_FLD_VAL',
        CASE WHEN rt.FLD_NAME = 'XYZ' THEN FLD_VAL ELSE NULL END 'XYZ_FLD_VAL',
        CASE WHEN rt.FLD_NAME = 'KLM' THEN FLD_VAL ELSE NULL END 'KLM_FLD_VAL'

        FROM @MAIN_TABLE MT
        INNER JOIN @REF_TABLE RT ON RT.ID_1 = MT.ID_1 AND RT.ID_2 = MT.ID_2
    ) A
    GROUP BY  A.ID_1,A.ID_2
) B
ON MT.ID_1 = B.ID_1
AND MT.ID_2 = B.ID_2

SELECT * FROM @MAIN_TABLE

---

您可以使用

PIVOT

表来处理此问题

UPDATE MN
SET MN.[ABC_VAL] = REF.ABC,
    MN.[KLM_VAL] = REF.KLM,
    MN.[XYZ_VAL] = REF.XYZ
FROM @MAIN_TABLE MN 
INNER JOIN 
(
SELECT * 
FROM @REF_TABLE
PIVOT 
(MIN([FLD_VAL])  FOR [FLD_NAME] IN ([ABC],[XYZ],[KLM])
)AS PIVOTTABLE)REF ON MN.[ID_1] = REF.[ID_1] AND MN.[ID_2] = REF.[ID_2]

select * from @MAIN_TABLE

---

谢谢但是，这不适用于具有不同FLD_名称值的组，因为它只更新一个值。例如，在给定的样本数据中，对于组ID_1=10，ID_2=100，它将仅更新为“ABC”