修复panic

wrapper/gorm_v2.go

@@ -143,7 +143,7 @@ func (g *Gorm) Trace(ctx context.Context, begin time.Time, fc func() (string, in
 		sql, affectRows = fc()
 	}
 
-	g.write(ctx, "SQL执行记录", consts.LogLevelInfo, map[string]any{
+	logData := map[string]any{
 		"db_flag":     g.flag,
 		"db_node":     g.node,
 		"begin_time":  start,
@@ -151,8 +151,12 @@ func (g *Gorm) Trace(ctx context.Context, begin time.Time, fc func() (string, in
 		"used_time":   (end - start) / 1e6,
 		"sql":         sql,
 		"affect_rows": affectRows,
-		"err":         err.Error(),
-	})
+		"err":         "",
+	}
+	if nil != err {
+		logData["err"] = err.Error()
+	}
+	g.write(ctx, "SQL执行记录", consts.LogLevelInfo, logData)
 }
 
 // write ...