Extending query builder with extract... it's currently H2Driver only.

gistfile1.scala

package slickdemo.experiments

import scala.slick.driver.{BasicStatementBuilderComponent, H2Driver}
import scala.language.implicitConversions

/**
 * Created with IntelliJ IDEA.
 * User: pedrofurla
 * Date: 18/07/13
 * Time: 19:00
 */


trait H2ExtraStatements extends H2Driver { self  =>
// Oracle style row nums brakes extending BasicStatementBuilderComponent directly, it's a direct extension of H2Driver

  import scala.slick.ast._
  import scala.slick.driver.QueryBuilderInput

  override def createQueryBuilder(input: QueryBuilderInput) = new QueryBuilder(input)
  
  class QueryBuilder(input: QueryBuilderInput) extends super.QueryBuilder(input)  {

    import scala.slick.util.MacroSupport.macroSupportInterpolation
    override def expr(n: Node, skipParens: Boolean = false) = {
      n match {
        case Extract(n @ _* ) =>
          val datePart = n(1).asInstanceOf[LiteralNode].value.asInstanceOf[String]
          b"""extract(`${datePart} from ${n(0)})"""
          //b"""extract(`${datePart} from ${date}"""
        case _ => super.expr(n, skipParens)
      }}

  }

  import scala.slick.ast.FunctionSymbol

  val Extract = new FunctionSymbol("Extract")
}

object H2ExtraDriver extends H2Driver with H2ExtraStatements {
  import org.joda.time.DateTime
  import scala.slick.lifted.{BaseTypeMapper, ExtensionMethods,Column, ConstColumn}
  import scala.slick.ast.{Node, LiteralNode}

  //type DATE = java.sql.Date
  type DATE = DateTime

  object DateTimeConstants {
    sealed trait DateTimeConstant

    val year = ConstColumn("YEAR")
    val month = ConstColumn("month")
    val day = ConstColumn("day")
    val hour = ConstColumn("hour")
    val minutes = ConstColumn("minutes")
    val seconds = ConstColumn("seconds")
  }

  class DateColumnExtensionMethods2[B1, P1](val c: Column[P1]) extends AnyVal with ExtensionMethods[B1, P1] {
    def year[R](implicit om: o#to[Int, R]) = extract(DateTimeConstants.year)//om(Extract.column[Int](n, LiteralNode("year")))
    def month[R](implicit om: o#to[Int, R]) = om(Extract.column[Int](n, LiteralNode("month")))
    def day[R](implicit om: o#to[Int, R]) = om(Extract.column[Int](n, LiteralNode("day")))
    def extract[R](e: Column[String])(implicit om: o#to[Int, R]) =
        om(Extract.column(n, Node(e)))
    /*def extract[P2](e: Column[P2])(implicit om: o#arg[JDATE, P2]#to[JDATE, Long]) =
      om(Library.-.column[JDATE](n, Node(e)))*/
  }

  implicit def dateColumnExtensionMethods2(c: Column[DATE])(implicit tm: BaseTypeMapper[DATE]) =
    new DateColumnExtensionMethods2[DATE,DATE](c)

}