View SQL query in Slick

Question

Is there a way to observe an SQL statement that will be generated by Query?
For example, I have this:
val q = actions.filter(v => v.actionHash === hash && v.carriedAt > past)
Can I view its underlying raw SQL?

Solution 1

Slick 2.X:

You can print the query statement as shown on the Slick documentation:

val invoker = q.invoker
val statement = q.selectStatement

For other type of statements look at insertStatement, deleteStatement and updateStatement.

Slick 3.X:

val res = table.filter(_.id === 1L).result
res.statements.foreach(println)

Docs.

Solution 2

For slick 3.0

println(sortedQuery.result.statements.headOption)

Comments

[wlk]

Works as well on Slick version 3.1.1

[Moha the almighty camel]

This doesn't work with DBIOAction, is there another way for this?

[Ende Neu]

@Mhd.Tahawi could you provide an example? I don't think I get your question.

[Justin du Coeur]

The thing is, .statements works fine for a SQLAction, but it doesn't exist for a DBIOAction, which is what you get when you compose a bunch of SQLActions together in a for comprehension and yield the final result. Far as I can tell, Monadic joins lose the ability to use .statements. That's kind of a pain...

[Ende Neu]

@JustinduCoeur right, I see that SQLAction is a subclass of DBIOAction and BasicAction and that the actual implementations are Invokers (like StreamingInvokerAction). Maybe the statement print can only be done at invoker level and not in the upper trait, unfortunately I don't have an answer for that.

[Justin du Coeur]

@EndeNeu Agreed, although I think it's a hole in the API. Ideally, traits like DBIOAction would provide a best-effort implementation of .statements, based on what they are compositing. Not the end of the world, but it was frustrating to discover the lack, given how useful .statements is for debugging...

[Tim Gautier]

DBIOAction can't implement .statements since DBIOAction doesn't even have to contain a SQL statement. It could be just about anything in there.