planner: Support assign DEFAULT in ON DUPLICATE KEY UPDATE statement

ddl/db_integration_test.go

@@ -1929,11 +1929,7 @@ func (s *testIntegrationSuite3) TestInsertIntoGeneratedColumnWithDefaultExpr(c *
 	tk.MustExec("create table t5 (a int default 10, b int as (a+1))")
 	tk.MustGetErrCode("insert into t5 values (20, default(a))", mysql.ErrBadGeneratedColumn)
 
-	tk.MustExec("drop table t1")
-	tk.MustExec("drop table t2")
-	tk.MustExec("drop table t3")
-	tk.MustExec("drop table t4")
-	tk.MustExec("drop table t5")
+	tk.MustExec("drop table t1, t2, t3, t4, t5")
 }
 
 func (s *testIntegrationSuite3) TestSqlFunctionsInGeneratedColumns(c *C) {

executor/write_test.go

@@ -796,6 +796,41 @@ func (s *testSuite4) TestInsertSetWithDefault(c *C) {
 	tk.MustExec("drop table t1, t2")
 }
 
+func (s *testSuite4) TestInsertOnDupUpdateDefault(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	// Assign `DEFAULT` in `INSERT ... ON DUPLICATE KEY UPDATE ...` statement
+	tk.MustExec("drop table if exists t1, t2;")
+	tk.MustExec("create table t1 (a int unique, b int default 20, c int default 30);")
+	tk.MustExec("insert into t1 values (1,default,default);")
+	tk.MustExec("insert into t1 values (1,default,default) on duplicate key update b=default;")
+	tk.MustQuery("select * from t1;").Check(testkit.Rows("1 20 30"))
+	tk.MustExec("insert into t1 values (1,default,default) on duplicate key update c=default, b=default;")
+	tk.MustQuery("select * from t1;").Check(testkit.Rows("1 20 30"))
+	tk.MustExec("insert into t1 values (1,default,default) on duplicate key update c=default, a=2")
+	tk.MustQuery("select * from t1;").Check(testkit.Rows("2 20 30"))
+	tk.MustExec("insert into t1 values (2,default,default) on duplicate key update c=default(b)")
+	tk.MustQuery("select * from t1;").Check(testkit.Rows("2 20 20"))
+	tk.MustExec("insert into t1 values (2,default,default) on duplicate key update a=default(b)+default(c)")
+	tk.MustQuery("select * from t1;").Check(testkit.Rows("50 20 20"))
+	// With generated columns
+	tk.MustExec("create table t2 (a int unique, b int generated always as (-a) virtual, c int generated always as (-a) stored);")
+	tk.MustExec("insert into t2 values (1,default,default);")
+	tk.MustExec("insert into t2 values (1,default,default) on duplicate key update a=2, b=default;")
+	tk.MustQuery("select * from t2").Check(testkit.Rows("2 -2 -2"))
+	tk.MustExec("insert into t2 values (2,default,default) on duplicate key update a=3, c=default;")
+	tk.MustQuery("select * from t2").Check(testkit.Rows("3 -3 -3"))
+	tk.MustExec("insert into t2 values (3,default,default) on duplicate key update c=default, b=default, a=4;")
+	tk.MustQuery("select * from t2").Check(testkit.Rows("4 -4 -4"))
+	tk.MustExec("insert into t2 values (10,default,default) on duplicate key update b=default, a=20, c=default;")
+	tk.MustQuery("select * from t2").Check(testkit.Rows("4 -4 -4", "10 -10 -10"))
+	tk.MustGetErrCode("insert into t2 values (4,default,default) on duplicate key update b=default(a);", mysql.ErrBadGeneratedColumn)
+	tk.MustGetErrCode("insert into t2 values (4,default,default) on duplicate key update a=default(b), b=default(b);", mysql.ErrBadGeneratedColumn)
+	tk.MustGetErrCode("insert into t2 values (4,default,default) on duplicate key update a=default(a), c=default(c);", mysql.ErrBadGeneratedColumn)
+	tk.MustGetErrCode("insert into t2 values (4,default,default) on duplicate key update a=default(a), c=default(a);", mysql.ErrBadGeneratedColumn)
+	tk.MustExec("drop table t1, t2")
+}
+
 func (s *testSuite4) TestReplace(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")

planner/core/logical_plan_builder.go

@@ -3020,7 +3020,7 @@ func (b *PlanBuilder) buildUpdateLists(
 		columnFullName := fmt.Sprintf("%s.%s.%s", name.DBName.L, name.TblName.L, name.ColName.L)
 		// We save a flag for the column in map `modifyColumns`
 		// This flag indicated if assign keyword `DEFAULT` to the column
-		if _, ok := extractDefaultExpr(assign.Expr); ok {
+		if extractDefaultExpr(assign.Expr) != nil {
 			modifyColumns[columnFullName] = true
 		} else {
 			modifyColumns[columnFullName] = false
@@ -3073,7 +3073,7 @@ func (b *PlanBuilder) buildUpdateLists(
 		var np LogicalPlan
 		if i < len(list) {
 			// If assign `DEFAULT` to column, fill the `defaultExpr.Name` before rewrite expression
-			if expr, ok := extractDefaultExpr(assign.Expr); ok {
+			if expr := extractDefaultExpr(assign.Expr); expr != nil {
 				expr.Name = assign.Column
 			}
 			newExpr, np, err = b.rewrite(ctx, assign.Expr, p, nil, false)
@@ -3115,15 +3115,14 @@ func (b *PlanBuilder) buildUpdateLists(
 	return newList, p, allAssignmentsAreConstant, nil
 }
 
-// extractDefaultExpr extract a `DefaultExpr` without any parameter from a `ExprNode`,
-// return the `DefaultExpr` and whether it's extracted successfully.
-// Note: the SQL function `DEFAULT(a)` is not the same with keyword `DEFAULT`,
-// SQL function `DEFAULT(a)` will return `false`.
-func extractDefaultExpr(node ast.ExprNode) (*ast.DefaultExpr, bool) {
+// extractDefaultExpr extract a `DefaultExpr` from `ExprNode`,
+// If it is a `DEFAULT` function like `DEFAULT(a)`, return nil.
+// Only if it is `DEFAULT` keyword, it will return the `DefaultExpr`.
+func extractDefaultExpr(node ast.ExprNode) *ast.DefaultExpr {
 	if expr, ok := node.(*ast.DefaultExpr); ok && expr.Name == nil {
-		return expr, true
+		return expr
 	}
-	return nil, false
+	return nil
 }
 
 func (b *PlanBuilder) buildDelete(ctx context.Context, delete *ast.DeleteStmt) (Plan, error) {

planner/core/planbuilder.go

@@ -1829,27 +1829,13 @@ func (b *PlanBuilder) buildInsert(ctx context.Context, insert *ast.InsertStmt) (
 
 	mockTablePlan.SetSchema(insertPlan.Schema4OnDuplicate)
 	mockTablePlan.names = insertPlan.names4OnDuplicate
-	columnByName := make(map[string]*table.Column, len(insertPlan.Table.Cols()))
-	for _, col := range insertPlan.Table.Cols() {
-		columnByName[col.Name.L] = col
-	}
-	onDupColSet, dupCols, dupColNames, err := insertPlan.validateOnDup(insert.OnDuplicate, columnByName, tableInfo)
+
+	onDupColSet, err := insertPlan.resolveOnDuplicate(insert.OnDuplicate, tableInfo, func(node ast.ExprNode) (expression.Expression, error) {
+		return b.rewriteInsertOnDuplicateUpdate(ctx, node, mockTablePlan, insertPlan)
+	})
 	if err != nil {
 		return nil, err
 	}
-	for i, assign := range insert.OnDuplicate {
-		// Construct the function which calculates the assign value of the column.
-		expr, err1 := b.rewriteInsertOnDuplicateUpdate(ctx, assign.Expr, mockTablePlan, insertPlan)
-		if err1 != nil {
-			return nil, err1
-		}
-
-		insertPlan.OnDuplicate = append(insertPlan.OnDuplicate, &expression.Assignment{
-			Col:     dupCols[i],
-			ColName: dupColNames[i].ColName,
-			Expr:    expr,
-		})
-	}
 
 	// Calculate generated columns.
 	mockTablePlan.schema = insertPlan.tableSchema
@@ -1863,29 +1849,51 @@ func (b *PlanBuilder) buildInsert(ctx context.Context, insert *ast.InsertStmt) (
 	return insertPlan, err
 }
 
-func (p *Insert) validateOnDup(onDup []*ast.Assignment, colMap map[string]*table.Column, tblInfo *model.TableInfo) (map[string]struct{}, []*expression.Column, types.NameSlice, error) {
+func (p *Insert) resolveOnDuplicate(onDup []*ast.Assignment, tblInfo *model.TableInfo, yield func(ast.ExprNode) (expression.Expression, error)) (map[string]struct{}, error) {
 	onDupColSet := make(map[string]struct{}, len(onDup))
-	dupCols := make([]*expression.Column, 0, len(onDup))
-	dupColNames := make(types.NameSlice, 0, len(onDup))
+	colMap := make(map[string]*table.Column, len(p.Table.Cols()))
+	for _, col := range p.Table.Cols() {
+		colMap[col.Name.L] = col
+	}
 	for _, assign := range onDup {
 		// Check whether the column to be updated exists in the source table.
 		idx, err := expression.FindFieldName(p.tableColNames, assign.Column)
 		if err != nil {
-			return nil, nil, nil, err
+			return nil, err
 		} else if idx < 0 {
-			return nil, nil, nil, ErrUnknownColumn.GenWithStackByArgs(assign.Column.OrigColName(), "field list")
+			return nil, ErrUnknownColumn.GenWithStackByArgs(assign.Column.OrigColName(), "field list")
 		}
 
 		// Check whether the column to be updated is the generated column.
 		column := colMap[assign.Column.Name.L]
+		isDefault := false
+		if expr := extractDefaultExpr(assign.Expr); expr != nil {
+			expr.Name = assign.Column
+			isDefault = true
+		}
+		// Note: For INSERT, REPLACE, and UPDATE, if a generated column is inserted into, replaced, or updated explicitly, the only permitted value is DEFAULT.
+		// see https://dev.mysql.com/doc/refman/8.0/en/create-table-generated-columns.html
 		if column.IsGenerated() {
-			return nil, nil, nil, ErrBadGeneratedColumn.GenWithStackByArgs(assign.Column.Name.O, tblInfo.Name.O)
+			if isDefault {
+				continue
+			}
+			return nil, ErrBadGeneratedColumn.GenWithStackByArgs(assign.Column.Name.O, tblInfo.Name.O)
 		}
+
 		onDupColSet[column.Name.L] = struct{}{}
-		dupCols = append(dupCols, p.tableSchema.Columns[idx])
-		dupColNames = append(dupColNames, p.tableColNames[idx])
+
+		expr, err := yield(assign.Expr)
+		if err != nil {
+			return nil, err
+		}
+
+		p.OnDuplicate = append(p.OnDuplicate, &expression.Assignment{
+			Col:     p.tableSchema.Columns[idx],
+			ColName: p.tableColNames[idx].ColName,
+			Expr:    expr,
+		})
 	}
-	return onDupColSet, dupCols, dupColNames, nil
+	return onDupColSet, nil
 }
 
 func (b *PlanBuilder) getAffectCols(insertStmt *ast.InsertStmt, insertPlan *Insert) (affectedValuesCols []*table.Column, err error) {
@@ -1941,14 +1949,15 @@ func (b *PlanBuilder) buildSetValuesOfInsert(ctx context.Context, insert *ast.In
 
 	insertPlan.AllAssignmentsAreConstant = true
 	for i, assign := range insert.Setlist {
-		defaultExpr, isDefaultExpr := extractDefaultExpr(assign.Expr)
-		if isDefaultExpr {
-			defaultExpr.Name = assign.Column
+		isDefault := false
+		if expr := extractDefaultExpr(assign.Expr); expr != nil {
+			expr.Name = assign.Column
+			isDefault = true
 		}
 		// Note: For INSERT, REPLACE, and UPDATE, if a generated column is inserted into, replaced, or updated explicitly, the only permitted value is DEFAULT.
 		// see https://dev.mysql.com/doc/refman/8.0/en/create-table-generated-columns.html
 		if _, ok := generatedColumns[assign.Column.Name.L]; ok {
-			if isDefaultExpr {
+			if isDefault {
 				continue
 			}
 			return ErrBadGeneratedColumn.GenWithStackByArgs(assign.Column.Name.O, tableInfo.Name.O)