如何为以下结果编写 SQL 查询？

Question

这是我当前的 table 数据：

Godown_Column	Product_Column	Quantity
Godown 1	Product 1	10
Godown 1	Product 2	20
Godown 2	Product 3	30
Godown 3	Product 3	40

此处，Godowns_Columns 具有不同货仓的无限行数。

如何编写 SQL 查询以获得此结果：

Product_Col	Godown 1	Godown 2	Godown 3
Product 1	10
Product 2	20
Product 3		30	40

Answer 1

WITH GODOWNS(Godown_Column,     Product_Column,     Quantity) AS
(
    SELECT 'Godown 1',  'Product 1',    10 UNION ALL
    SELECT 'Godown 1',  'Product 2',    20 UNION ALL
    SELECT 'Godown 2',  'Product 3',    30 UNION ALL
    SELECT 'Godown 3',  'Product 3',    40
)
SELECT D.Product_Column,
  MAX(CASE WHEN Godown_Column='Godown 1' THEN QUANTITY ELSE 0 END)AS GODOWN_1,
  MAX(CASE WHEN Godown_Column='Godown 2' THEN QUANTITY ELSE 0 END)AS GODOWN_2,
  MAX(CASE WHEN Godown_Column='Godown 3' THEN QUANTITY ELSE 0 END)AS GODOWN_3
FROM GODOWNS AS D
GROUP BY D.Product_Column

GODOWNS 是你的数据示例。请将对它的引用替换为对实际 table

的引用

Answer 2

您可以使用动态数据透视表，因为仓库数量未知。

架构：

 create table mytable(Godown_Column varchar(50),    Product_Column  varchar(50), Quantity int)
 insert into mytable values('Godown 1', 'Product 1' ,10);
 insert into mytable values('Godown 1', 'Product 2' ,20);
 insert into mytable values('Godown 2', 'Product 3' ,30);
 insert into mytable values('Godown 3', 'Product 3' ,40);

查询：

 DECLARE @cols  AS NVARCHAR(MAX)='';
 DECLARE @query AS NVARCHAR(MAX)='';
 
 
 SET @cols = STUFF((SELECT distinct ',' + quotename(Godown_Column)
             FROM mytable
             FOR XML PATH(''), TYPE
             ).value('.', 'NVARCHAR(MAX)') 
         ,1,1,'')
         
 
 set @query = 'SELECT Product_Column,' + @cols  + '
              from 
              (
 select * from mytable
              ) x
             pivot 
             (
                 sum(quantity)
                 for Godown_Column in (' + @cols + ')
             ) p'
 
 execute(@query)

输出：

Product_Column	Godown 1	Godown 2	Godown 3
Product 1	10	null	null
Product 2	20	null	null
Product 3	null	30	40

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