allow select aliases to be in group by/having

Author: angelamayxie

sql/planbuilder/project.go

@@ -135,7 +135,7 @@ func (b *Builder) analyzeSelectList(inScope, outScope *scope, selectExprs ast.Se
 					err := sql.ErrColumnNotFound.New(gf.String())
 					b.handleErr(err)
 				}
-				col = scopeColumn{id: id, tableId: gf.TableId(), col: e.Name(), db: gf.Database(), table: gf.Table(), scalar: e, typ: gf.Type(), nullable: gf.IsNullable()}
+				col = scopeColumn{id: id, tableId: gf.TableId(), col: e.Name(), db: gf.Database(), table: gf.Table(), typ: gf.Type(), nullable: gf.IsNullable(), originalCol: gf.Name()}
 			} else if sq, ok := e.Child.(*plan.Subquery); ok {
 				col = scopeColumn{col: e.Name(), scalar: e, typ: sq.Type(), nullable: sq.IsNullable()}
 			} else {
@@ -151,6 +151,10 @@ func (b *Builder) analyzeSelectList(inScope, outScope *scope, selectExprs ast.Se
 				col.scalar = e
 				tempScope.addColumn(col)
 			}
+			if inScope.selectColumnAliases == nil {
+				inScope.selectColumnAliases = make(map[string]scopeColumn)
+			}
+			inScope.selectColumnAliases[e.Name()] = col
 			exprs = append(exprs, e)
 		default:
 			exprs = append(exprs, pe)

sql/planbuilder/scalar.go

@@ -123,14 +123,16 @@ func (b *Builder) buildScalar(inScope *scope, e ast.Expr) (ex sql.Expression) {
 		colName := strings.ToLower(v.Name.String())
 		c, ok := inScope.resolveColumn(dbName, tblName, colName, true, false)
 		if !ok {
+			alias, ok := inScope.selectColumnAliases[colName]
+			if ok {
+				return alias.scalarGf()
+			}
 			sysVar, scope, ok := b.buildSysVar(v, ast.SetScope_None)
 			if ok {
 				return sysVar
 			}
 			var err error
-			if scope == ast.SetScope_User {
-				err = sql.ErrUnknownUserVariable.New(colName)
-			} else if scope == ast.SetScope_Persist || scope == ast.SetScope_PersistOnly {
+			if scope == ast.SetScope_User || scope == ast.SetScope_Persist || scope == ast.SetScope_PersistOnly {
 				err = sql.ErrUnknownUserVariable.New(colName)
 			} else if scope == ast.SetScope_Global || scope == ast.SetScope_Session {
 				err = sql.ErrUnknownSystemVariable.New(colName)

sql/planbuilder/scope.go

@@ -61,6 +61,8 @@ type scope struct {
 
 	insertTableAlias    string
 	insertColumnAliases map[string]string
+
+	selectColumnAliases map[string]scopeColumn
 }
 
 // resolveColumn matches a variable use to a column definition with a unique
@@ -644,8 +646,11 @@ func (c scopeColumn) withOriginal(origTbl, col string) scopeColumn {
 // scalarGf returns a getField reference to this column's expression.
 func (c scopeColumn) scalarGf() sql.Expression {
 	if c.scalar != nil {
-		if p, ok := c.scalar.(*expression.ProcedureParam); ok {
-			return p
+		switch e := c.scalar.(type) {
+		case *expression.ProcedureParam:
+			return e
+		case *expression.Alias:
+			return e.Child
 		}
 	}
 	if c.originalCol != "" {