Question

我试图在查询返回的值（表名）中进行搜索，以检查是否有记录，并且该记录中的某些值为空。如果是，那么我想将表的名称插入临时表。我收到一个错误：

Conversion failed when converting the varchar value 'count(*) 
FROM  step_inusd_20130618 WHERE jobDateClosed IS NULL' to data type int.

这是查询：

  DECLARE @table_name VARCHAR(150)
  DECLARE @sql VARCHAR(1000)
  DECLARE @test int

  SELECT @table_name =  tableName FROM  #temp WHERE id = @count

   SET @sql = 'SELECT * FROM  ' + @table_name + ' WHERE jobDateClosed IS NULL'
--ERROR is below:
select @test =   'count(*) FROM  ' + @table_name + ' WHERE jobDateClosed IS NULL'
   --PRINT @sql
  -- EXEC(@sql)
   IF @test > 0 
   BEGIN 
    INSERT INTO #temp2 (tablename) VALUES ( @table_name);
   END
  SET @count = @count + 1

如何将计数结果转换为整数？

Answer 1

检查sp_executesql您可以在哪里定义输出参数。

DECLARE @table_name VARCHAR(150)
DECLARE @sql VARCHAR(1000)
DECLARE @test int

SELECT @table_name =  tableName FROM  #temp WHERE id = @count

DECLARE @SQLString nvarchar(500);
DECLARE @ParmDefinition nvarchar(500);

SET @SQLString = N'SELECT @test = count(*) FROM  ' + @table_name + ' WHERE jobDateClosed IS NULL'
SET @ParmDefinition = N'@test int OUTPUT';

EXECUTE sp_executesql @SQLString, @ParmDefinition, @test=@test OUTPUT;

IF @test > 0 
    BEGIN 
        INSERT INTO #temp2 (tablename) VALUES ( @table_name);
    END
SET @count = @count + 1

Answer 2

不应该＆＃34; SET＆＃34;而不是＆＃34;选择＆＃34; ？

例如，改变：

select @test =   'count(*) FROM  ' + @table_name + ' WHERE jobDateClosed IS NULL'

有：

SET @test =   'select count(*) FROM  ' + @table_name + ' WHERE jobDateClosed IS NULL'

Answer 3

正如我所看到的，你的问题是，$ test变量是INT，你试图为它分配TEXT值＆＃39; count ...＆＃39;

使用aproach如：选择somevalue INTO myvar from mytable WHERE uid = 1;

Answer 4

我修剪了不需要的东西来展示如何做到这一点，所以这里是：

DECLARE @table_name VARCHAR(150)
DECLARE @CountStatement NVARCHAR(1000)
DECLARE @test int

SELECT @table_name =  tableName FROM  #temp WHERE id = @count

SET @CountStatement = 'select @test = count(*) FROM  ' + @table_name + ' WHERE jobDateClosed IS NULL'
EXECUTE sp_executesql @CountStatement, N'@test INT OUTPUT', @test OUTPUT;
SELECT @test

将动态sql查询的COUNT结果转换为INT

4 个答案: