Fix expression String methods

engine.go

@@ -579,9 +579,9 @@ func (e *Engine) bindExecuteQueryNode(ctx *sql.Context, query string, eq *plan.E
 
 	// TODO: overwrite the current binding if bindings are not empty???
 	tempBindings := make(map[string]sql.Expression)
-	for i, name := range eq.BindVars {
-		if strings.HasPrefix(name.String(), "@") {
-			t, val, err := ctx.GetUserVariable(ctx, strings.TrimPrefix(name.String(), "@"))
+	for i, binding := range eq.BindVars {
+		if userVar, ok := binding.(*expression.UserVar); ok {
+			t, val, err := ctx.GetUserVariable(ctx, userVar.Name)
 			if err != nil {
 				return nil, nil
 			}
@@ -596,7 +596,7 @@ func (e *Engine) bindExecuteQueryNode(ctx *sql.Context, query string, eq *plan.E
 			}
 			tempBindings[fmt.Sprintf("v%d", i+1)] = expression.NewLiteral(val, t)
 		} else {
-			tempBindings[fmt.Sprintf("v%d", i)] = name
+			tempBindings[fmt.Sprintf("v%d", i)] = binding
 		}
 	}
 

enginetest/queries/prepared_statement_queries.go

@@ -94,6 +94,7 @@ var PreparedScriptTests = []ScriptTest{
 			"set @a = 1",
 			"set @b = 100",
 			"set @c = 'abc'",
+			"set @schema = 'reserved name'",
 		},
 		Assertions: []ScriptTestAssertion{
 			{
@@ -134,6 +135,12 @@ var PreparedScriptTests = []ScriptTest{
 					{"abc"},
 				},
 			},
+			{
+				Query: "execute s using @schema",
+				Expected: []sql.Row{
+					{"reserved name"},
+				},
+			},
 			{
 				Query: "deallocate prepare s",
 				Expected: []sql.Row{

enginetest/queries/queries.go

@@ -9366,7 +9366,7 @@ from typestable`,
 			{"Project"},
 			{" ├─ columns: [count(1)]"},
 			{" └─ Project"},
-			{"     ├─ columns: [mytable.COUNT(1) as COUNT(1)]"},
+			{"     ├─ columns: [mytable.COUNT(1) as `COUNT(1)`]"},
 			{"     └─ table_count(mytable) as COUNT(1)"},
 		},
 	},