[parser] Revert "parser,ast: fix the TiDB issue #8153 (#20)" (#24)

pingcap · Oct 9, 2021 · 9cf3037 · 9cf3037
1 parent 53c43f7
commit 9cf3037
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Showing 3 changed files with 14 additions and 17 deletions.
diff --git a/parser/ast/expressions.go b/parser/ast/expressions.go
@@ -699,7 +699,7 @@ func (n *ParenthesesExpr) Accept(v Visitor) (Node, bool) {
 type PositionExpr struct {
 	exprNode
 	// N is the position, started from 1 now.
-	N ExprNode
+	N int
 	// Refer is the result field the position refers to.
 	Refer *ResultField
 }
@@ -716,13 +716,6 @@ func (n *PositionExpr) Accept(v Visitor) (Node, bool) {
 		return v.Leave(newNode)
 	}
 	n = newNode.(*PositionExpr)
-	if n.N != nil {
-		node, ok := n.N.Accept(v)
-		if !ok {
-			return n, false
-		}
-		n.N = node.(ExprNode)
-	}
 	return v.Leave(n)
 }
 

diff --git a/parser/parser.go b/parser/parser.go
diff --git a/parser/parser.y b/parser/parser.y
@@ -3188,11 +3188,13 @@ ByItem:
 	Expression Order
 	{
 		expr := $1
-		if valueExpr, ok := expr.(ast.ValueExpr); ok {
-			expr = &ast.PositionExpr{N: valueExpr}
-		} else if paramExpr, ok := expr.(ast.ParamMarkerExpr); ok {
-			expr = &ast.PositionExpr{N: paramExpr}
- 		}
+		valueExpr, ok := expr.(ast.ValueExpr)
+		if ok {
+			position, isPosition := valueExpr.GetValue().(int64)
+			if isPosition {
+				expr = &ast.PositionExpr{N: int(position)}
+			}
+		}
 		$$ = &ast.ByItem{Expr: expr, Desc: $2.(bool)}
 	}