SQL QUERY TO SELECT ALL VALUES

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im passing user value in c# to sql
it may be null or any value.
eg; @city='chennai' or ''

My query : select FirstName from AdmissionTbl where City=@city
if @city='' then it should retrieve all records else only 'chennai' records.
it works only for selected('chennai') value. if it is null it doesn't retrieve any records.
how to query in sql?

Posted 15-Feb-13 18:28pm

sukumari1

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Sheikh Muhammad Haris · Answer 1 · 2013-02-15T18:31:00

Solution 1

SQL

SELECT FirstName FROM AdmissionTbl (NOLOCK) WHERE (City=@City OR @City IS NULL OR @City = '')

Posted 15-Feb-13 18:31pm

Sheikh Muhammad Haris

Abhinav S · Answer 2 · 2013-02-15T18:32:00

Solution 2

Since you have C# code in the front end, simply check if you need to pass in a city,
If you don't have to, don't add the parameter to the code and also skip the where clause.

Posted 15-Feb-13 18:32pm

Abhinav S

Prince P Ravi · Answer 3 · 2013-02-15T18:37:00

Solution 3

SQL

SELECT FirstName from AdmissionTbl where City=@city OR CITY IS NULL ;

SELECT CASE WHEN FirstName  IS NULL THEN 'NO VALUE' ELSE  FirstName   where City=@city OR CITY IS NULL ;

Posted 15-Feb-13 18:37pm

Prince P Ravi

Comments

[no name] 16-Feb-13 1:07am

For checking Null values in a column, case is not better, try using isnull() function. And use parenthesis () when using OR in your queries.

SELECT isnull(FirstName, 'No-Name') as FirstName from mytable where ( City=@city OR CITY IS NULL )

Prince P Ravi 16-Feb-13 6:16am

thanks Mr.sheik