Fix CI failures: enum string formatting and query test expectations

- Fix ErrInvalidType formatting issue in enum.go - use fmt.Sprintf for type
- Fix query test expectations: INSERT returns OkResult, not empty rows
- Address multiple CI test failures with enum zero handling

Author: elianddb

enginetest/queries/script_queries.go

@@ -9058,7 +9058,7 @@ where
 			{
 				// Test enum with explicit empty string - should allow 0
 				Query:    "insert into t_empty values (0);",
-				Expected: []sql.Row{{}},
+				Expected: []sql.Row{{types.OkResult{RowsAffected: 1}}},
 			},
 			{
 				Query:    "select e from t_empty;",
@@ -9079,7 +9079,7 @@ where
 			{
 				// In non-strict mode, 0 should be allowed and convert to empty string
 				Query:    "insert into t values (0);",
-				Expected: []sql.Row{{}},
+				Expected: []sql.Row{{types.OkResult{RowsAffected: 1}}},
 			},
 			{
 				Query:    "select e from t;",

sql/expression/enum.go

@@ -14,6 +14,8 @@
 package expression
 
 import (
+	"fmt"
+
 	"github.com/dolthub/go-mysql-server/sql"
 	"github.com/dolthub/go-mysql-server/sql/types"
 )
@@ -80,7 +82,7 @@ func (e *EnumToString) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)
 	case string:
 		str = v
 	default:
-		return nil, sql.ErrInvalidType.New(val, types.Text)
+		return nil, sql.ErrInvalidType.New(fmt.Sprintf("%T", val))
 	}
 	return str, nil
 }