Difference between select * from table & select individual columns from table

Database

Difference between select * from table & select individual columns from table

Hello all,
I am having trouble understanding difference select * from TABLE X or select a , b, c ( columns) from table X ( same table ) above.
I was wondering if someone actually knows what is the difference at the Teradata DB Architecture level.

Thanks,
Aditi
3 REPLIES

Re: Difference between select * from table & select individual columns from table

There would be slight performance improvement when you use explicit list of columns in SELECT stmt, instead of having ‘*’, but I don’t think there is any difference at DB Architecture level

Re: Difference between select * from table & select individual columns from table

Hi,

AFAIK there will not be any performance difference between "select * " and "select column_lists", since the optimizer will generate same plan for both the query.

Regards,
Balamurugan

Re: Difference between select * from table & select individual columns from table

You can use sel top10* from table to get quicker result sets, instead of going for sel * from table , if you want to check the columns and their names, for one instance. Fetch time will be minimized.