This code implements a facility for Slick 1.0.1 to inject custom SQL instead of the Slick produced SQL to be used when running a query

gistfile1.scala

import scala.slick.lifted._
import scala.slick.ast._
import scala.slick.driver._

/** Extends QueryInvoker to allow overriding used SQL statement when executing a query */
trait OverridingInvoker extends BasicDriver{
  // get the extended QueryInvoker into the .simple._ implicits
  override val Implicit: Implicits = new Implicits
  override val simple: Implicits with SimpleQL = new Implicits with SimpleQL
  class Implicits extends super.Implicits {
    override implicit def queryToQueryInvoker[T, U](q: Query[T, _ <: U]): QueryInvoker[T, U] = new QueryInvoker(q)
  }

  // extended QueryInvoker
  class QueryInvoker[Q, R](q: Query[Q, _ <: R]) extends super.QueryInvoker[Q, R](q) {
    def overrideSql(sql: String) = new PatchedQueryInvoker(sql,q)
  }

  // QueryInvoker that patches the used SQL
  class PatchedQueryInvoker[P,U](sql:String, q: Query[P,U]) extends QueryInvoker(q){
      override def getStatement = sql
  }
}

// Create a custom MySQL driver patching in the Overriding invoker
object CustomMySQLDriver extends MySQLDriver with OverridingInvoker

object Main extends App{
  // Import stuff from the patched driver instead of the default
  import CustomMySQLDriver.simple._
  // please fill in jdbc connection url and driver
  Database.forURL("...", driver = "...") withSession {
    // tamper with SQL statement
    val munged = Query(Suppliers).selectStatement + " where SUP_ID = 49"
    // inject munged version
    println(Query(Suppliers).overrideSql(munged).list)
  }
}

Updated code for Slick 2.0 can be found in here: https://gist.github.com/cvogt/d9049c63fc395654c4b4

There is a PR to add this feature natively to Slick 2.1 slick/slick#810

Hi, Chris,

Thanks a million for doing the 2.0 port. We were just starting a new project using 2.0 and I'd instructed my colleague to work on porting the 1.0 code you supplied. Fortunately, he found this.

I hear through the grapevine you've got a new gig. Good luck!