diff --git a/library/think/db/Builder.php b/library/think/db/Builder.php
index cd948dad..d2297a4c 100644
--- a/library/think/db/Builder.php
+++ b/library/think/db/Builder.php
@@ -116,14 +116,10 @@ abstract class Builder
                         $result[$item] = $val[1];
                         break;
                     case 'inc':
-                        if ($key == $val[1]) {
-                            $result[$item] = $this->parseKey($val[1]) . '+' . floatval($val[2]);
-                        }
+                        $result[$item] = $item . '+' . floatval($val[2]);
                         break;
                     case 'dec':
-                        if ($key == $val[1]) {
-                            $result[$item] = $this->parseKey($val[1]) . '-' . floatval($val[2]);
-                        }
+                        $result[$item] = $item . '-' . floatval($val[2]);
                         break;
                 }
             } elseif (is_scalar($val)) {
diff --git a/library/think/db/Query.php b/library/think/db/Query.php
index 50f0fd85..43fe2745 100644
--- a/library/think/db/Query.php
+++ b/library/think/db/Query.php
@@ -828,7 +828,7 @@ class Query
     {
         $fields = is_string($field) ? explode(',', $field) : $field;
         foreach ($fields as $field) {
-            $this->data($field, ['inc', $field, $step]);
+            $this->data($field, ['inc', $step]);
         }
         return $this;
     }
@@ -844,7 +844,7 @@ class Query
     {
         $fields = is_string($field) ? explode(',', $field) : $field;
         foreach ($fields as $field) {
-            $this->data($field, ['dec', $field, $step]);
+            $this->data($field, ['dec', $step]);
         }
         return $this;
     }