I have table with some column fields are name studentid and status(yes/no)

If i want to find out those records which have same studentid but different status?

What should i do?

select * from table where status = 1 and studentid in (select studentid from table where status = 0)

 

 

... status(yes/no)

...

 

There is no need for a string datatype for your status field (unless you are using Access and the boolean datatype which stores "Yes" or "No" in a string format)

For MySQL databases you can use TINYINT(1) to create a boolean type. The field could contain two values then: 0 and 1. (If you allow null you would technically have 3 values)

This would optimize your select statement a lot as it takes time for the database to scan string values.

 

 

There is no need for a string datatype for your status field (unless you are using Access and the boolean datatype which stores "Yes" or "No" in a string format)

For MySQL databases you can use TINYINT(1) to create a boolean type. The field could contain two values then: 0 and 1. (If you allow null you would technically have 3 values)

This would optimize your select statement a lot as it takes time for the database to scan string values.

I actually think a more appropriate datatype to use in this case would be ENUM

I actually think a more appropriate datatype to use in this case would be ENUM

Good point. That would keep your database slim and save you from converting the values to strings programmatically