我认为这不是一个好主意，但您实际上并没有执行您创建的@SQL，您只是在选择它。
您的代码容易受到 SQL 注入的影响（因为您直接执行带有连接参数的 sql），所以要小心该代码。
另外，如果你存储的是数字，为什么你的数据类型是varchar(30)？您的其他数据类型是 float（应该是 numeric/decimal 而不是 float）。
你可以像这样使用exec sp_executesql @SQL：
CREATE PROC addCurrency @CurrencyName varchar(30),@Rupee float,
@Euro float,@Dollar float,@Pound float
AS
BEGIN
INSERT into [dbo].[CurrencyTbl] (CurrencyName , Rupee,Euro, Dollar,Pound )
VALUES (@CurrencyName,@Rupee,@Euro,@Dollar,@Pound )
END
BEGIN
Declare @SQL nVarChar(1000)
SELECT @SQL = 'ALTER TABLE [dbo].[CurrencyTbl] ADD ' + @CurrencyName + ' float;'
exec sp_executesql @SQL;
END
动态sql
例如：
/* Monies is the term used by Irkens to refer to their form of currency */
exec addCurrency 'Monies',1,1,1,1
select * from CurrencyTbl
rextester 演示：http://rextester.com/CUC99912
返回：
+------------+--------------+------------+----------+----------+----------+--------+
| CurrencyID | CurrencyName | Rupee | Euro | Dollar | Pound | Monies |
+------------+--------------+------------+----------+----------+----------+--------+
| 1 | Rupee | 1,000000 | 0,008000 | 0,009000 | 0,007000 | NULL |
| 2 | Euro | 121,300000 | 1,000000 | 1,080000 | 0,840000 | NULL |
| 3 | Dollar | 111,400000 | 0,910000 | 1,000000 | 0,770000 | NULL |
| 4 | Pound | 143,600000 | 1,180000 | 1,280000 | 1,000000 | NULL |
| 5 | Monies | 1,000000 | 1,000000 | 1,000000 | 1,000000 | NULL |
+------------+--------------+------------+----------+----------+----------+--------+
最好为您的表考虑一种不需要添加新列和使用动态 sql 更新列的替代形式。
这是一种选择：
create table CurrencyTbl (FromCurrencyName varchar(30), ExchangeRate decimal(19,6), ToCurrencyName varchar(30))
insert into CurrencyTbl values
('Rupee ',1.000000,'Rupee')
,('Rupee ',0.008000,'Euro')
,('Rupee ',0.009000,'Dollar')
,('Rupee ',0.007000,'Pound')
,('Euro ',121.300000,'Rupee')
,('Euro ',1.000000,'Euro')
,('Euro ',1.090000,'Dollar')
,('Euro ',0.850000,'Pound')
,('Dollar',111.400000,'Rupee')
,('Dollar',0.910000,'Euro')
,('Dollar',1.000000,'Dollar')
,('Dollar',0.770000,'Pound')
,('Pound ',143.600000,'Rupee')
,('Pound ',1.180000,'Euro')
,('Pound ',1.280000,'Dollar')
,('Pound ',1.000000,'Pound')
您可以像这样动态地旋转表格：
declare @cols nvarchar(max);
declare @sql nvarchar(max);
select @cols = stuff((
select distinct
', ' + quotename(ToCurrencyName)
from CurrencyTbl
for xml path (''), type).value('.','nvarchar(max)')
,1,1,'')
select @sql = '
select FromCurrencyName as CurrencyName,' + @cols + '
from CurrencyTbl
pivot (max([ExchangeRate]) for [ToCurrencyName] in (' + @cols + ') ) p'
exec sp_executesql @sql;
rextester 演示：http://rextester.com/EQSC62833
返回：
+--------------+----------+----------+----------+------------+
| CurrencyName | Dollar | Euro | Pound | Rupee |
+--------------+----------+----------+----------+------------+
| Dollar | 1,000000 | 0,910000 | 0,770000 | 111,400000 |
| Euro | 1,090000 | 1,000000 | 0,850000 | 121,300000 |
| Pound | 1,280000 | 1,180000 | 1,000000 | 143,600000 |
| Rupee | 0,009000 | 0,008000 | 0,007000 | 1,000000 |
+--------------+----------+----------+----------+------------+