[英]Create a function for counting rows from any table
我有這個用戶定義的功能:
CREATE FUNCTION [dbo].[COUNT_ROWS_TABLE]()
RETURNS TINYINT
AS
BEGIN
DECLARE @ROW_COUNT TINYINT
SELECT @ROW_COUNT = COUNT(*) FROM EMPLOYEE
RETURN @ROW_COUNT
END
GO
問題是它僅適用於表[dbo].[EMPLOYEE]
並且我不想為數據庫中的每個表復制粘貼此函數。
到目前為止我的嘗試:
CREATE FUNCTION [dbo].[COUNT_ROWS_TABLE](@TABLE_NAME VARCHAR(50))
RETURNS TINYINT
AS
BEGIN
DECLARE @SQL_COMMAND NVARCHAR(100)
DECLARE @PARAM NVARCHAR(50)
DECLARE @ROW_COUNT TINYINT
SET @SQL_COMMAND = N'SELECT @RESULT = COUNT(*) FROM ' + @TABLE_NAME
SET @PARAM = N'@RESULT TINYINT OUTPUT'
EXEC SP_EXECUTESQL @SQL_COMMAND, @PARAM, @RESULT = @ROW_COUNT OUTPUT
RETURN @ROW_COUNT
END
GO
該代碼不起作用,因為它不允許在函數中包含這些語句。 雖然它在存儲過程中起作用,但是僅當我PRINT
變量而不是RETURN
變量時才起作用。
我需要將它作為一個函數,因為我需要在IF
語句上調用它。
關於如何實現這一點的任何想法? 謝謝。
您可以像下面這樣使用
ALTER FUNCTION [dbo].[COUNT_ROWS_TABLE](@TABLE_NAME VARCHAR(50))
RETURNS TINYINT
AS
BEGIN
DECLARE @ROW_COUNT TINYINT
SELECT @ROW_COUNT = SUM(b.rows)
FROM SYS.TABLES a INNER JOIN sys.partitions b ON b.OBJECT_ID = a.OBJECT_ID
WHERE a.is_ms_shipped = 0 AND b.index_id IN (1,0)
and a.name=@TABLE_NAME
GROUP BY a.name
RETURN @ROW_COUNT
END
GO
對於將對象名作為參數傳遞的這種查詢,您將需要使用Dynamic Sql,但是由於您僅返回總行數,因此使用sys模式目錄視圖和Dynamic sql可以實現這一點,因此無法使用UDF定義內的動態Sql。
這是您需要做的.....
CREATE PROCEDURE [dbo].[COUNT_ROWS_TABLE]
@TABLE_NAME SYSNAME,
@Count INT OUTPUT
AS
BEGIN
SET NOCOUNT ON;
DECLARE @Sql NVARCHAR(MAX);
SET @Sql = N'SELECT @Count = COUNT(*) FROM ' + QUOTENAME(@TABLE_NAME)
EXECUTE sp_executesql @Sql
, N'@Count INT OUTPUT'
, @Count OUTPUT
END
GO
CREATE FUNCTION [dbo].[COUNT_ROWS_TABLE]
(
@TableName SYSNAME
)
RETURNS INT
AS
BEGIN
DECLARE @Row_Count INT;
SELECT @Row_Count = i.rowcnt
FROM sysindexes AS i
INNER JOIN sysobjects AS o ON i.id = o.id
WHERE i.indid < 2 AND OBJECTPROPERTY(o.id, 'IsMSShipped') = 0
AND o.NAME = @TableName
RETURN @Row_Count;
END
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