如何将动态SQL的结果存储在变量中？

我有以下理论声明，我想使用动态SQL（在SQL Server 2016上）实现并将单个输出值存储在变量（@output）中。如何将动态SQL的结果存储在变量中？

@numericvar,@columnname,@tablename应该是输入参数。任何帮助将不胜感激。非常感谢。

SELECT @output = (
    SELECT 
     MAX(CASE WHEN ROWNUM*1.0/NUMROWS <= @numericvar THEN @columnname END) 
    FROM (
     SELECT 
      @columnname, 
      ROW_NUMBER() OVER (ORDER BY @columnname) AS ROWNUM, 
      COUNT(*) OVER (PARTITION BY NULL) AS NUMROWS 
     FROM 
      @tablename 
    ) @tablename 
);

来源

2016-11-05 Kanarinox

DECLARE @columnname SYSNAME, @tablename SYSNAME, @numericvar NUMERIC(18,2); 
DECLARE @output NUMERIC(18,2); 

DECLARE @sql NVARCHAR(MAX) = N' 
    SET @output = (
     SELECT 
      MAX(CASE WHEN ROWNUM*1.0/NUMROWS <= @numericvar THEN '+QUOTENAME(@columnname)+N' END) 
     FROM (
      SELECT 
       '+QUOTENAME(@columnname)+N', 
       ROW_NUMBER() OVER (ORDER BY '+QUOTENAME(@columnname)+N') AS ROWNUM, 
       COUNT(*) OVER (PARTITION BY NULL) AS NUMROWS 
      FROM 
       '+QUOTENAME(@tablename)+N' 
     ) AS t 
    ); 
'; 

EXECUTE sp_executesql 
    @sql, 
    N'@numericvar NUMERIC(18,2), @output NUMERIC(18,2) OUTPUT', 
    @numericvar, @output OUTPUT; 

SELECT @output;

更新：为FLOAT输出工作的例子。该脚本使用每个人都有的INFORMATION_SCHEMA架构中的表格。

看看你是否可以使它从这个样本工作。如果你不能，我建议你编辑你的问题，并添加你正在使用的确切的脚本+参数值+指示的列名类型。

DECLARE @schemaname SYSNAME='INFORMATION_SCHEMA', 
     @tablename SYSNAME='COLUMNS', 
     @columnname SYSNAME='NUMERIC_PRECISION', 
     @numericvar NUMERIC(18,2)=.5; 

DECLARE @output_f FLOAT; 

DECLARE @sql NVARCHAR(MAX) = N' 
    SET @output_f = (
      SELECT 
       MAX(CASE WHEN ROWNUM*1.0/NUMROWS<[email protected] THEN '+QUOTENAME(@columnname)+N' END) 
      FROM (
       SELECT 
        '+QUOTENAME(@columnname)+N', 
        ROW_NUMBER() OVER (ORDER BY '+QUOTENAME(@columnname)+N') AS ROWNUM, 
        COUNT(*) OVER() AS NUMROWS 
       FROM 
        '+QUOTENAME(@schemaname)+N'.'+QUOTENAME(@tablename)+N' 
      ) AS t 
    ); 
'; 

EXECUTE sp_executesql 
    @sql, 
    N'@numericvar NUMERIC(18,2), @output_f FLOAT OUTPUT', 
    @numericvar, @output_f OUTPUT; 

SELECT @output_f;

来源

2016-11-05 14:54:56

我得到一个算术溢出错误，将nvarchar转换为数据类型数字。 – Kanarinox

@Kanarinox你对变量'@ output'的类型做了什么？你在'@ columnname'中传递的列的类型是什么？ –

浮球和浮球。（请原谅反应迟滞，我是gmt + 4）。 – Kanarinox

试试这个，我把复制粘贴在这里和那里，你可能需要解决一下以防万一。

declare @query nvarchar(max) 
declare @output nvarchar(max) 
declare @columnname nvarchar(max) 
declare @tablename nvarchar(max) 
declare @numericvar NUMERIC(18,0) 

    set @query ='SELECT @output = (
     SELECT 
      MAX(CASE WHEN ROWNUM*1.0/NUMROWS <= @numericvar THEN @columnname END) 
     FROM (
      SELECT 
       @columnname, 
       ROW_NUMBER() OVER (ORDER BY @columnname) AS ROWNUM, 
       COUNT(*) OVER (PARTITION BY NULL) AS NUMROWS 
      FROM 
       @tablename 
     ) @tablename 
    );' 

    exec sp_executesql @query, N'@output numeric(18,2) output, 
    @columnname nvarchar(max), declare @numericvar NUMERIC(18,0), 
    declare @tablename nvarchar(max)', @output= @output output, @columnname= @columnname, @[email protected], @[email protected] 
    select @output

来源

2016-11-05 15:01:39 James

如何将动态SQL的结果存储在变量中？

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