Rewrite update queries into selects

Author: kormoc

classes/QueryRewrite.php

@@ -35,6 +35,8 @@ function figureOutType(){
 				$this->type = self::INSERT;
 			elseif (preg_match('/^(.*)\s+UNION\s+(.*)$/', $this->sql))
 				$this->type = self::UNION;
+			elseif (preg_match('/^UPDATE\s/', $this->sql))
+				$this->type = self::UPDATE;
 			else
 				$this->type = self::UNKNOWN;
 		}
@@ -48,6 +50,9 @@ function toSelect() {
 					return preg_replace('/^DELETE\s+FROM\s/', 'SELECT 0 FROM ', $this->sql);
 				case self::DELETEMULTI:
 					return preg_replace('/^DELETE\s+'.self::TABLEREF.'\s+FROM\s/', 'SELECT 0 FROM ', $this->sql);
+				case self::UPDATE:
+					preg_match('/^UPDATE\s+(.*)\s+SET\s+(.*)\s+WHERE\s+(.*)$/', $this->sql, $subpatterns);
+					return "SELECT {$subpatterns[2]} FROM {$subpatterns[1]} WHERE {$subpatterns[3]}";
 			}
 			return null;
 		}
@@ -60,6 +65,7 @@ function asExplain() {
 					break;
 				case self::DELETE:
 				case self::DELETEMULTI:
+				case self::UPDATE:
 					$sql = $this->toSelect();
 					break;
 				default:

explain.php

@@ -15,6 +15,9 @@
 	$Query = new QueryRewrite($query);
 	$sample = $Query->asExtendedExplain();
 
+	$return['oQuery'] = $query;
+	$return['eQuery'] = $sample;
+	
 	if (is_null($sample)) {
 		$return['Warnings'][] = array('Code' => '0', 'Level' => 'Error', 'Message' => "I can't explain this type of query yet");
 	}