sql - 用于计算动态表项的 MS SQL 存储过程

Question

我在存储过程下面写了这个，得到了不正确的语句。

ALTER PROCEDURE dbo.[Counter]
        @TableName VARCHAR(100)
    AS 
        BEGIN
            DECLARE @Counter INT
            DECLARE @SQLQ VARCHAR(200)
            SET NOCOUNT ON;

        --SET @TableName = 'Member';
        SET @SQLQ = 'SELECT COUNT(*) FROM dbo.[' + @TableName + ']';
        --Preparing the above sql syntax into a new statement(get_counter).

            --Getting an error here I had googled the prepare statement but don't know why facing this error.
        PREPARE get_counter FROM @SQLQ;
    @Counter = EXEC get_counter; -- here @resutl gets the value of the count.@TableName
        DEALLOCATE PREPARE get_counter; -- removing the statement from the memory.


    END

然后我又写了一篇:

ALTER PROCEDURE dbo.[Counter]
    @TableName VARCHAR(100)
AS 
    BEGIN
        DECLARE @Counter INT
        DECLARE @SQLQ VARCHAR(200)
        SET NOCOUNT ON;

        --SET @TableName = 'Member';
        SET @SQLQ = 'SELECT COUNT(*) FROM dbo.[' + @TableName + ']';
        --Preparing the above sql syntax into a new statement(get_counter).


    Execute @SQLQ; -- here @resutl gets the value of the count.@TableName

        --DEALLOCATE PREPARE get_counter; -- removing the statement from the memory.
        Return @Counter;

    END

它运行良好，但我无法在 Counter 中获得结果，请任何人帮助我(我知道我没有为计数器分配任何值，但如果我这样做，我会出错)。

在您回答马丁之后，我现在用您的代码替换了我的代码:

ALTER PROCEDURE dbo.[Counter] @SchemaName SYSNAME = 'dbo' , @TableName  SYSNAME

AS
  BEGIN
      SET NOCOUNT ON;

      DECLARE @SQLQ NVARCHAR(1000)
      DECLARE @Counter INT;

      SET @SQLQ = 'SELECT @Counter = COUNT(*) FROM ' + 
       Quotename(@SchemaName) + '.' + Quotename(@TableName);

      EXEC sp_executesql
        @SQLQ ,
        N'@Counter INT OUTPUT',
        @Counter = @Counter OUTPUT

      Return   SELECT @Counter
  END 

现在我已经找回了它。

  ALTER PROCEDURE dbo.[CreateBusinessCode]
    @MemberID                               bigint,
    @len                                        int,
    @RewardAccountID                bigint,
    @ConnectionStatusID         tinyint,
    @Assign                                 smalldatetime

AS
    BEGIN
    SET NOCOUNT ON;
    DECLARE @counter INT

    EXEC @counter = dbo.Counter 'dbo','member';

    Select @counter;


    END

Answer 1

您应该使用 SYSNAME用于对象标识符和 Quotename而不是自己连接方括号。

ALTER PROCEDURE dbo.[Counter] @TableName  SYSNAME,
                              @SchemaName SYSNAME = 'dbo'
AS
  BEGIN
      SET NOCOUNT ON;

      DECLARE @SQLQ NVARCHAR(1000)
      DECLARE @Counter INT;

      SET @SQLQ = 'SELECT @Counter = COUNT(*) FROM ' + 
       Quotename(@SchemaName) + '.' + Quotename(@TableName);

      EXEC sp_executesql
        @SQLQ ,
        N'@Counter INT OUTPUT',
        @Counter = @Counter OUTPUT

         SELECT @Counter
  END