统计学时问题修复

@@ -2089,12 +2089,16 @@ function birthday_old($id){
 function id_xueshi($id){
     $name = Db::name('yuyue')
         ->where(['uid'=>$id,'status'=>'3'])
-        ->count();
-    return $name;
+        ->field(' SUM(yuyue_end - yuyue_begin) as yyxs ')
+        ->select();
+    $yyxs = $name ? $name['yyxs'] : 0;
+    return $yyxs;
 }
 function tid_xueshi($id){
     $name = Db::name('yuyue')
         ->where(['teach_id'=>$id,'status'=>'3'])
-        ->count();
-    return $name;
+        ->field(' SUM(yuyue_end - yuyue_begin) as yyxs ')
+        ->select();
+    $yyxs = $name ? $name['yyxs'] : 0;
+    return $yyxs;
 }
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