Select Statement Query in MySQL

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Hi,,plz help me.

SQL

SELECT *
FROM  `studentdetails`
WHERE Community =  'BC'
AND Department ='CSE'

This statement selects the rows which are have cse and bc in their department and community columns.
Simliarly i used this.

SQL

SELECT *
FROM  `studentdetails`
WHERE Community =  'BC'
AND Department ='CSE' AND Rank >100

I want to use the previous query for dynamic inputs. Please tel me how to get all community students above rank 100 belongs to CSE dept. I just want to know, which value i have to put for all community students in the place "Community= ".

Posted 26-Jul-11 11:45am

suyambu123

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JOAT-MON · Answer 1 · 2011-07-26T12:44:00

You don't. You remove the 'Community=' and just use the columns you want to filter on:

SQL

...WHERE Department = 'CSE' AND Rank > 100

This will let the database engine know not to use Community as a filter column.

If you are trying to make one query that will handle both queries above, then maybe you could try using LIKE statement:

SQL

... WHERE Community LIKE '%' AND Department = 'CSE' AND Rank > 100

This would only be reliable is your Community values were made up of distinctive character combinations, so that when specifying a community you would only get that one community, rather than all that match the character combination.

[EDIT]
I may not be understanding your question, so please explain it better if this does not answer what you are trying to ask.

You cannot use any wildcard characters in equality filters, meaning you cannot have the pattern ColumnName = '%', you can only use the wildcard characters with the LIKE construct for pattern matching when filtering results.

In order to include a particular column in the WHERE clause and not have it limit anything from your results, you need to use the pattern ColumnName LIKE '%'. This will match all entries in the column.