Remove initial Literal in Where clause in SQL Server module (#712)

sqlserver/src/main/scala/zio/sql/sqlserver/SqlServerRenderModule.scala

@@ -60,12 +60,7 @@ trait SqlServerRenderModule extends SqlServerSqlModule { self =>
  render(" FROM ")
  buildTable(t)
  }
- whereExpr match {
- case Expr.Literal(true) => ()
- case _ =>
- render(" WHERE ")
- buildExpr(whereExpr)
- }
+ buildWhereExpr(whereExpr)
  groupByExprs match {
  case Read.ExprSet.ExprCons(_, _) =>
  render(" GROUP BT ")
@@ -96,7 +91,7 @@ trait SqlServerRenderModule extends SqlServerSqlModule { self =>
  render(" (", values.mkString(","), ") ") // todo fix needs escaping
  }
 
- def buildExpr[A, B](expr: self.Expr[_, A, B])(implicit render: Renderer): Unit = expr match {
+ private def buildExpr[A, B](expr: self.Expr[_, A, B])(implicit render: Renderer): Unit = expr match {
  case Expr.Subselect(subselect) =>
  render(" (")
  render(renderRead(subselect))
@@ -126,7 +121,11 @@ trait SqlServerRenderModule extends SqlServerSqlModule { self =>
  case Expr.Relational(left, right, op) =>
  buildExpr(left)
  render(" ", op.symbol, " ")
- buildExpr(right)
+ right.asInstanceOf[Expr[_, A, B]] match {
+ case Expr.Literal(true) => val _ = render("1")
+ case Expr.Literal(false) => val _ = render("0")
+ case otherValue => buildExpr(otherValue)
+ }
  case Expr.In(value, set) =>
  buildExpr(value)
  renderReadImpl(set)
@@ -247,7 +246,7 @@ trait SqlServerRenderModule extends SqlServerSqlModule { self =>
  render(")")
  }
 
- def buildExprList(expr: Read.ExprSet[_])(implicit render: Renderer): Unit  =
+ private def buildExprList(expr: Read.ExprSet[_])(implicit render: Renderer): Unit =
  expr match {
  case Read.ExprSet.ExprCons(head, tail) =>
  buildExpr(head)
@@ -259,7 +258,8 @@ trait SqlServerRenderModule extends SqlServerSqlModule { self =>
  }
  case Read.ExprSet.NoExpr => ()
  }
- def buildOrderingList(expr: List[Ordering[Expr[_, _, _]]])(implicit render: Renderer): Unit =
+
+ private def buildOrderingList(expr: List[Ordering[Expr[_, _, _]]])(implicit render: Renderer): Unit =
  expr match {
  case head :: tail =>
  head match {
@@ -277,7 +277,7 @@ trait SqlServerRenderModule extends SqlServerSqlModule { self =>
  case Nil => ()
  }
 
- def buildSelection(selectionSet: SelectionSet[_])(implicit render: Renderer): Unit =
+ private def buildSelection(selectionSet: SelectionSet[_])(implicit render: Renderer): Unit =
  selectionSet match {
  case cons0 @ SelectionSet.Cons(_, _) =>
  object Dummy {
@@ -295,7 +295,7 @@ trait SqlServerRenderModule extends SqlServerSqlModule { self =>
  case SelectionSet.Empty => ()
  }
 
- def buildColumnSelection[A, B](columnSelection: ColumnSelection[A, B])(implicit render: Renderer): Unit =
+ private def buildColumnSelection[A, B](columnSelection: ColumnSelection[A, B])(implicit render: Renderer): Unit =
  columnSelection match {
  case ColumnSelection.Constant(value, name) =>
  render(value.toString()) // todo fix escaping
@@ -317,7 +317,7 @@ trait SqlServerRenderModule extends SqlServerSqlModule { self =>
  }
  }
 
- def buildTable(table: Table)(implicit render: Renderer): Unit =
+ private def buildTable(table: Table)(implicit render: Renderer): Unit =
  table match {
 
  case Table.DerivedTable(read, name) =>
@@ -356,15 +356,24 @@ trait SqlServerRenderModule extends SqlServerSqlModule { self =>
  render(" ")
  }
 
+ /**
+ * Drops the initial Litaral(true) present at the start of every WHERE expressions by default 
+ * and proceeds to the rest of Expr's.
+ */
+ private def buildWhereExpr[A, B](expr: self.Expr[_, A, B])(implicit render: Renderer): Unit = expr match {
+ case Expr.Literal(true) => ()
+ case Expr.Binary(_, b, _) =>
+ render(" WHERE ")
+ buildExpr(b)
+ case _ =>
+ render(" WHERE ")
+ buildExpr(expr)
+ }
+
  def renderDeleteImpl(delete: Delete[_])(implicit render: Renderer) = {
  render("DELETE FROM ")
  buildTable(delete.table)
- delete.whereExpr match {
- case Expr.Literal(true) => ()
- case _ =>
- render(" WHERE ")
- buildExpr(delete.whereExpr)
- }
+ buildWhereExpr(delete.whereExpr)
  }
 
  // TODO https://github.com/zio/zio-sql/issues/160