fix: fix the return type of dropColumn function.

Author: ping-yee

system/Database/Forge.php

@@ -796,6 +796,11 @@ public function dropColumn(string $table, $columnNames)
             return false;
         }
 
+        // If _alterTable() return execute result instead of sql string, return.
+        if ((bool) $sql === true) {
+            return true;
+        }
+
         return $this->db->query($sql);
     }
 

system/Database/SQLite3/Forge.php

@@ -126,11 +126,12 @@ protected function _alterTable(string $alterType, string $table, $processedField
 
                 $sqlTable = new Table($this->db, $this);
 
-                $sqlTable->fromTable($table)
+                $sqlExecuteResult = $sqlTable->fromTable($table)
                     ->dropColumn($columnNamesToDrop)
                     ->run();
 
-                return ''; // Why empty string?
+                // Return the execute result with string type.
+                return '' . $sqlExecuteResult;
 
             case 'CHANGE':
                 $fieldsToModify = [];

tests/system/Database/Live/ForgeTest.php

@@ -1317,7 +1317,8 @@ public function testDropColumn(): void
 
         $this->assertTrue($this->db->fieldExists('name', 'forge_test_two'));
 
-        $this->forge->dropColumn('forge_test_two', 'name');
+        $result = $this->forge->dropColumn('forge_test_two', 'name');
+        $this->assertTrue($result);
 
         $this->db->resetDataCache();