# Query Translation

Query translation enables the SQL Relay server to modify queries before passing them to the database. This is useful for things like:

Normalizing queries for more effective query filtering:

> From:

> >     sElEcT
> >     	*,
> >     	'He' || 'Ll' || 'o'
> >     from
> >     	myTABLE
> >     where
> >     	myTaBLe.CoLuMn1    =     myTablE.ColuMN2  /    2

> To:

> >     select *, 'HeLlo' from mytable where mytable.column1 = mytable.column2/2

Migrating an application to use a different database backend without modifying the application itself:

> From:

> >     create table mysqltable (col1 tinytext, col2 mediumtext)

> To:

> >     create table oracletable (col1 varchar2(254), col2 varchar2(1023))

A complete descripton of query translation with example configuration files is given here.