任何人都可以解释这个SQL代码的行为...... [英] Can Anyone Explain the Behaviour of this Sql Code......

问题描述

DECLARE @Scrap_Qty int
DECLARE @FilledQty int
SET @Scrap_Qty=10 --Change this to 1 and it still Shows Same O/P
SET @FilledQty = 2
 
BEGIN
 
IF @Scrap_Qty > @FilledQty
 declare @currDate varchar(10)   
 Set @currDate= Convert(VARCHAR(10),GetDate(),103)  
 PRINT @currDate
 
END   

输出为：

The Output is:

07/06/2013

在所有情况下如果cond'n为False也显示o / p ......我知道没有开始和结束语句....但是无法理解这个行为如果stmt ...声明不是可执行文件...我知道......



任何解释都会有所帮助.....



（来自奇怪和精彩页面的原始问题发表于Virang_21）

（本代码不是由我写的......我不会写这种代码......）

in all cases if the cond'n is False also it's Showing the o/p...... I Know there is no Begin and End Statements.... But Unable to understand the Behaviour of this if stmt... Declare is not a Executable stmt.. i know...

Any Explanation Will be helpful.....

(Original Question from The Weird and Wonderful Page posted by Virang_21)
(This Code is not Written by me.. I Won't Ever write This Kind of Code...)

推荐答案

我认为您的BEGIN语句位于错误的位置，因此IF语句仅适用于声明@currDate varchar（10），这意味着接下来的两个语句将始终执行。 BEGIN语句应该是IF语句之后的第一个语句。



问候，

Ian。

I think your BEGIN statement is in the wrong place, so the IF statement only applies to the "declare @currDate varchar(10)", which means the next two statements will always execute. The BEGIN statement should be the first statement after the IF statement.

Regards,
Ian.

你好，



SQL Server没有块级变量作用域[ ^ 。因此，你的if语句导致什么都不执行，因为下一个语句是DECLARE并且是一个不可执行的语句。其余两个语句作为usal执行，因此你总是看到curDate的值被打印。



问候，

Hello,

SQL Server does not have block level variable scoping[^]. And hence your if statement results in executing nothing because the next statement is DECLARE AND is a non-executable statement. The rest two statements execute as usal and therefore you always see the value of curDate getting printed.

Regards,

你需要在你的if语句中添加括号如：IF（@Scrap_Qty> @FilledQty）

然后它将起作用



喜欢

You need to put brackets like : IF (@Scrap_Qty > @FilledQty)
in your if statement then it will work

like

  IF (@Scrap_Qty > @FilledQty)
print 'y'

然后它将读取第一个语句

then it will read the first statement

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