difference between these two queries?

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SQL

SELECT DBName, ConnString + '#VIJAY#' + FinanceConnString + '#VIJAY#' +
RptDBConnString AS ConStr FROM [DataBase] WHERE Active = 1

select dbname, connstring as ConStr from [database] where active=1

giving same result,so what is the diff between above two queries?Plz explain...

in 1st query why we r using+ '#VIJAY#' + FinanceConnString + '#VIJAY#' +
RptDBConnString

Posted 26-Dec-12 18:29pm

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Sergey Alexandrovich Kryukov 27-Dec-12 0:43am

Don't you think this is totally incorrect question, a totally wrong approach to asking question?
You gave a query and ask "why do we use" this or in it. No, you please tell us why do you write it this way. And ask a real question.
—SA

StackQ 27-Dec-12 1:17am

i m not getting u.But u r senior,so i agree with u,may be approach is not right,but i just want to know diff bet them? And plz help me how should i ask for this question to know diff bet them?

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__TR__ · Accepted Answer · 2012-12-26T18:42:00

Solution 1

The 2 queries will give same result if ConnString column is NULL because
NULL + Anything is NULL.
To see the difference between 2 queries use ISNULL[^]
Try

SQL

SELECT DBName, ISNULL(ConnString,'') + '#VIJAY#' + ISNULL(FinanceConnString,'') + '#VIJAY#' +
ISNULL(RptDBConnString,'') AS ConStr FROM [DataBase] WHERE Active = 1

Posted 26-Dec-12 18:42pm

__TR__

Comments

StackQ 27-Dec-12 1:20am

no,i just want to know why we r using:- +'#VIJAY#' + FinanceConnString + '#VIJAY#' +
in my 1st query,bcoz this query is not written by me,it's written by another person,so i want to know why we r using it?

__TR__ 27-Dec-12 1:27am

I don't have any idea on why was the query written like that. You may want to check it with the person who actually wrote it.
The + is used for concatenating 2 columns in the query
Take a look at this article
SQL Concatenation[^]

StackQ 27-Dec-12 1:37am

ya i got my answe:Explaining:-

In my table database(columns are dbname,connstring,financeconnstring,rptdbstring)

by my 1st query it select all connstrings but shows only for dbname and connstring,and remaining exist in background according to 1st query.

but when i run this query:-SELECT + '#VIJAY#' + FinanceConnString + '#VIJAY#' +

RptDBConnString AS ConStr FROM [DataBase] WHERE Active = 1

then it shows all the background/hidden query of financeconnstring and rptdbconnstring.

thnx for ur effort also.

StackQ 27-Dec-12 1:39am

http://blog.sqlauthority.com/2010/11/25/sql-server-concat-function-in-sql-server-sql-concatenation/

this link helps me.