[SilverRed]

I have never worked somewhere that has a dedicated database person. The SQL goes in the application code so it is the developers job to commit stuff which is performant and safe.

There is no point having developers write sql at all if someone else has to come in and redo it after.

[AdrianB1]

I have a team of 4 people doing part time exactly this: improving performance of queries from various apps. My team does not know the business logic (many apps, not enough people), the developers don't have the knowledge to build good SQL code for databases with tables of hundreds of GB each. If you write small web apps it is not a problem, but if you have hundreds of servers with that size of databases, development DBAs are a must.