util, types: don't let SPM be affected by charset

types/parser_driver/value_expr.go

@@ -103,6 +103,7 @@ func (n *ValueExpr) Restore(ctx *format.RestoreCtx) error {
 		// This part is used to process flag HasStringWithoutDefaultCharset, which means if we have this flag and the
 		// charset is mysql.DefaultCharset, we don't need to write the default.
 		if n.Type.Charset != "" &&
+			!ctx.Flags.HasStringWithoutCharset() &&
 			(!ctx.Flags.HasStringWithoutDefaultCharset() || n.Type.Charset != mysql.DefaultCharset) {
 			ctx.WritePlain("_")
 			ctx.WriteKeyWord(n.Type.Charset)

util/parser/ast.go

@@ -55,8 +55,8 @@ func RestoreWithDefaultDB(node ast.StmtNode, defaultDB string) string {
 	// Three flags for restore with default DB:
 	// 1. RestoreStringSingleQuotes specifies to use single quotes to surround the string;
 	// 2. RestoreSpacesAroundBinaryOperation specifies to add space around binary operation;
-	// 3. RestoreStringWithoutDefaultCharset specifies to not print default charset before string;
-	ctx := format.NewRestoreCtx(format.RestoreStringSingleQuotes|format.RestoreSpacesAroundBinaryOperation|format.RestoreStringWithoutDefaultCharset, &sb)
+	// 3. RestoreStringWithoutCharset specifies to not print charset before string;
+	ctx := format.NewRestoreCtx(format.RestoreStringSingleQuotes|format.RestoreSpacesAroundBinaryOperation|format.RestoreStringWithoutCharset, &sb)
 	ctx.DefaultDB = defaultDB
 	if err := node.Restore(ctx); err != nil {
 		return ""