Question

我想评估保存在sql server

中的变量中的数学表达式

我谷歌这很多，找到3个解决方案，但在我的方案中不适用

1-此解决方案 无法在函数 中执行，但我需要在函数内部

declare @expression nvarchar(max)
set @expression = '2*3*100'

declare @sql nvarchar(max)
set @sql = 'select @result = ' + @expression

declare @result int
exec sp_executesql @sql, N'@result int output', @result = @result out

select @result

2-此 无法保存到变量 ，但我需要将结果存储到变量中

DECLARE @LocalVariable VARCHAR(32);
SET @LocalVariable = '2*3*100';
EXEC('SELECT ' + @LocalVariable);

3-我发现的最后一个解决方案 给我一个错误

DECLARE @x xml 
DECLARE @v decimal(20,4) 
SET @x = '' 
DECLARE @calculatedDataString nvarchar(1000) = '(1 div 100)*((118 div 100)*300.000000)' 
SET @v= @x.value('sql:variable("@calculatedDataString")', 'decimal(20,4)') 
SELECT @v

错误

Msg 8114, Level 16, State 5, Line 5
Error converting data type nvarchar to numeric.

请提供建议

Answer 1

最后一个解决方案失败，因为SET @v= @x.value('sql:variable("@calculatedDataString")', 'decimal(20,4)')没有评估表达式，它会尝试将@calculatedDataString强制转换为十进制，这在大多数情况下肯定会失败。

我所知道的唯一解决方案是CLR功能。您可能希望查看此项目https://github.com/zzzprojects/Eval-SQL.NET

它使用您可以使用的方法创建SQLNET UDT，种类

SELECT  SQLNET::New(@calculatedDataString).EvalInt()

有关如何在sql-server中注册UDT，请参阅https://docs.microsoft.com/en-us/sql/relational-databases/clr-integration-database-objects-user-defined-types/registering-user-defined-types-in-sql-server。

Answer 2

也许这可能有所帮助。

以下将评估一系列表达式，将结果保存到#temp表中。从那里，您可以将单个结果存储到变量

中

这是一个大幅缩减的版本。完整的替代品是为宏观替代品建立的（即计算多个数据集的系列或财务比率）

如果您提供更强大的使用案例，也许我可以提供更多帮助

示例

Declare @Expression table (ID int,Expression varchar(max)) Insert Into @Expression values (1,'(1/100.0)*((118/100.0)*300.00000)') -- Simple Calculation ,(2,'datediff(DD,''2016-07-29'',GetDate())') -- System Functions ,(3,'(Select max(name) from master..spt_values)') -- Select Value From Table ,(4,'convert(date,GetDate())') -- Get Today's Date IF OBJECT_ID(N'tempdb..#Results') IS NOT NULL BEGIN DROP TABLE #Results END Create table #Results (ID int,Value varchar(max)) Declare @SQL varchar(max)='' Select @SQL = @SQL+concat(',(',ID,',cast(',Expression,' as varchar(max)))') From @Expression Select @SQL = 'Insert Into #Results Select * From ('+Stuff(@SQL,1,1,'values')+') N(ID,Value)' Exec(@SQL) Select * From #Results Declare @Var decimal(10,4) = (Select Value From #Results where ID=1) Select @Var -- 3.5400

临时表

ID Value 1 3.54000000000000000 2 243 3 YES OR NO 4 2017-03-29

Answer 3

这是我生产多年的解决方案。鉴于RegEx的强大功能，令人惊讶的是没有提供的解决方案。

这使用了安全的CLR程序集，该程序集确实假定了某些服务器级别的访问权限。这意味着在某些情况下，这可能不适用于AWS RDS或Azure SQL的托管实例以外的其他任何实例（例如新的“无服务器”选项）。

我目前正在具有此限制的Azure SQL实例中测试R语言的实现。感谢：https://www.mssqltips.com/sqlservertip/4748/sql-server-2016-regular-expressions-with-the-r-language/

CREATE ASSEMBLY [TESTSCORING1_CLR_CS]
FROM 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
WITH PERMISSION_SET = SAFE
GO


CREATE FUNCTION [dbo].[EvaluateArithmethicExpression](@expression [nvarchar](4000))
RETURNS [float] WITH EXECUTE AS CALLER
AS 
EXTERNAL NAME [TESTSCORING1_CLR_CS].[TESTSCORING1.ArithmeticCalculations].[EvaluateArithmethicExpression]
GO

-- Demo some simple evaluations
SELECT [dbo].[EvaluateArithmethicExpression]('1<10') as one, [dbo].[EvaluateArithmethicExpression]('1+1') as two, [dbo].[EvaluateArithmethicExpression]('300/100') as three
GO

如何评估SQL Server中保存在nvarchar变量中的数学表达式

3 个答案: