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Databases Querying Relational Databases Joining Table Data with SQL Inner Joins

Posted by Ra Bha
Ra Bha
2,201 Points

If the tables are aliased to md and mk, how come the column names don't change when query is run?

I get that you can alias the table names to mk and md as in the example. But when I run the query

SELECT mk.MakeName, md.ModelName FROM make AS mk INNER JOIN model AS md ON mk.MakeID = md.MakeID;

I see that the output table still has column names MakeName and ModelName.

Why is this? And what then is the purpose of aliasing the table names as in the example?

1 Answer

cgeorge
cgeorge
5,492 Points

Hello,

You may have already figured it out but you are giving the alias mk to the table name make.

SELECT - tells the database what columns to bring back. FROM- tells the database what table those columns belong to

so, FROM make AS mk is saying rename make table mk. If you want to give the column name an alias you need to use the AS keyword in the SELECT. SELECT mk.MakeName AS make, md.ModelName AS model FROM make AS mk INNER JOIN model AS md ON mk.MakeID = md.MakeID

I wouldn't give a column the same name as an alias though. It might get confusing.

I hope this helps. :)