Why not write simple SQL queries and use another language to do the transformations?
Are SQL engines really more efficient at filtering/matching/aggregating data when doing complex queries? Doesn't working without reusable blocks / tests / logs make development harder?
Syntax is one thing, but actual performance (and safety/maintenance) is another deal?
As others have said, yes. In most cases, the more complex the query the better the result.
> Doesn't working without reusable blocks / tests / logs make development harder?
SQL isn't a programming language, it's a query language. You're effectively writing a single expression that describes the shape of the data that you want and then then the RDBMS goes off and finds the most performant way to retrieve the data that matches that shape. It doesn't compare well with procedural programming.
The closest "languages" that comparable to SQL are HTML and CSS. However you manage HTML and CSS is also how you can manage SQL.