SQL 存儲過程筆記

一、SQL 存儲過程之遊標

--- 使用遊標循環 SQL 查詢結果：
--- 聲明變量
DECLARE @bid nvarchar(30);
DECLARE @address nvarchar(50);
--- 定義遊標
DECLARE cur CURSOR for 
		select bid,[Address]  from building;
--- 打開遊標
OPEN  cur 
	FETCH cur INTO @bid, @address
	
	WHILE   @@FETCH_STATUS=0   --- 遊標狀態
	    BEGIN 
	        print @bid + ', ' + @address
	        
	        update B_LDZ set CZWDZ = @address where BID = @bid

	        FETCH cur INTO @bid, @address  --- 移到下一位置
	    END
CLOSE cur  --- 關閉遊標
DEALLOCATE cur  --- 刪除遊標

二、SQL 解析字符串列表

2.1 遍歷字符串列表

--- SET @s='appNum1,appNum2,appNum3,appNum4,appNum5,appNum6,appNum7,appNum8,'     

CREATE PROCEDURE [dbo].[pro_split_str]
	@s nvarchar(1000)
AS
BEGIN

DECLARE @bid nvarchar(30)

SET @s= 'appNum1,appNum2,appNum3,appNum4,appNum5,appNum6,appNum7,appNum8,' 

WHILE CHARINDEX(',',@s)>0     
    BEGIN     
        SET @bid = LEFT(@s,CHARINDEX(',',@s)-1)

	print @bid  --- 輸出分隔內容，執行SQL或存儲過程	

        SET @s=RIGHT(@s,LEN(@s)-CHARINDEX(',',@s))     
    END 
END

GO

2.2 存儲過程之 IN 參數

2.2.1 CHARINDEX 分隔字符串

--- 聲明臨時表及參數
declare @TempTable Table(id nvarchar(10),name int)
declare @s nvarchar(100)
set @s = 'a,b'

--- 添加數據
insert @TempTable  select 'a',1 union all select 'b',2 
	union all select 'c',5 union all select 'd',8
	
--- 檢索數據,相當於 where id in @s
select * from @TempTable where CHARINDEX(','+id+',',','+@s+',')>0
 
/*
id	name
a	1
b	2
*/

2.2.2 創建函數分隔字符串

--- 把含分隔符的字符串轉換爲表
--- @str = 'a,b,c,d'
CREATE FUNCTION [dbo].[Split]  
(  
	@str VARCHAR(MAX) ,  
	@split VARCHAR(50)  
)  
RETURNS @t TABLE ( col VARCHAR(50) )  
AS  
BEGIN  
    WHILE ( CHARINDEX(@split, @str) <> 0 )  
        BEGIN  
            INSERT  @t( col )  
            VALUES  ( SUBSTRING(@str, 1, CHARINDEX(@split, @str) - 1) )  
            SET @str = STUFF(@str, 1, CHARINDEX(@split, @str), '')  
        END  
    INSERT  @t( col ) VALUES  ( @str )  
    RETURN  
END 

--- 測試
select * from dbo.split('a,b,c,d' , ',')
/*
col
-----
a
b
c
d
*/

應用時使用：select * from table where id in dbo.split('a,b,c')