Question

此表的“符号”列为：

我想将其转换为一个表格，该表格将Symbol的列值（不同）作为新的Column Name。这些列的类型应为bool或INT（0/1）。结果表应如下所示：

P.S。如果列集是由另一个查询动态生成的，怎么办？

Answer 1

只需使用case：

select (case when symbol = 'ACRX' then 1 else 0 end) as acrx,
       (case when symbol = 'ANF' then 1 else 0 end) as anf,
       (case when symbol = 'NVDA' then 1 else 0 end) as nvda,
       (case when symbol = 'rsx' then 1 else 0 end) as rsx,
       partofday, isprofitable
from t;

Answer 2

你可以做

select 
  IIF('ACRX', 1, 0) as acrx,
  IIF('ANF', 1, 0) as anf,
  IIF('NVDA', 1, 0) as nvda,
  IIF('RXS', 1, 0) as rsx,
  partofday, 
  isprofitable
from t;

Answer 3

如果需要动态列，则需要动态SQL

示例

Declare @SQL varchar(max) = Stuff((Select Distinct ',' + QuoteName(Symbol)+'=case when symbol='''+Symbol+''' then 1 else 0 end ' From Yourtable  Order by 1 For XML Path('')),1,1,'') 

Select @SQL = '
Select '+@SQL+'
      ,PartOfDay
      ,isProfitable
 From  YourTable
'
Exec(@SQL)

返回

Answer 4

您还可以将数据透视运算符应用于动态SQL。

例如：

create table test03
(
Symbol varchar(30),
PartOfDay int,
isProfitable int
)

insert into test03 values
('ACRX',3,0),
('ACRX',3,0),
('ANF',2,1),
('ANF',2,1),
('ANF',2,1),
('NVDA',3,1),
('RSX',3,0),
('RSX',3,0)

--Query

DECLARE @V_COLUMNS VARCHAR(MAX)
DECLARE @V_SQL VARCHAR(MAX)
SET @V_COLUMNS=STUFF((SELECT DISTINCT ','+QUOTENAME(Symbol) FROM test03 FOR XML PATH('')),1,1,'')
--print @V_COLUMNS

SET @V_SQL='
;WITH CTE AS
(
select 
ROW_NUMBER() over (order by Symbol) as RN,
Symbol,
1 AS V_VALUE,
PartOfDay,
isProfitable
from test03
)
SELECT '+@V_COLUMNS+',PartOfDay,isProfitable
FROM CTE 
PIVOT 
(
COUNT(V_VALUE) FOR Symbol IN ('+@V_COLUMNS+')
) PVT'

--PRINT @V_SQL
EXEC(@V_SQL)

--Output
/*
ACRX        ANF         NVDA        RSX         PartOfDay   isProfitable
----------- ----------- ----------- ----------- ----------- ------------
1           0           0           0           3           0
1           0           0           0           3           0
0           1           0           0           2           1
0           1           0           0           2           1
0           1           0           0           2           1
0           0           1           0           3           1
0           0           0           1           3           0
0           0           0           1           3           0
*/

SQL-将符号的列值转换为以符号作为名称和布尔类型的列

4 个答案: