[MySQL] Treat decimal as numeric-string (#429)

* Treat decimal as numeric-string

* record?

* no error here

* please new version of phpstan

* record with mysql 8

* Wrap accessory numeric string type in intersection type

Author: marmichalski

.phpstan-dba-mysqli.cache

@@ -83,7 +83,6 @@ protected function simulateQuery(string $queryString)
                 $columnMeta['flags'][] = $flag;
             }
 
-            // @phpstan-ignore-next-line
             $this->cache[$queryString][$columnIndex] = $columnMeta;
             ++$columnIndex;
         }

.phpstan-dba-pdo-mysql.cache

@@ -117,13 +117,20 @@ public function mapToPHPStanType(string $mysqlType, array $mysqlFlags, int $leng
             $phpstanType = IntegerRangeType::fromInterval(0, 2155);
         }
         // floats are detected as numerics in mysqli
-        if (\in_array(strtoupper($mysqlType), ['DOUBLE', 'NEWDECIMAL', 'REAL'], true)) {
+        if (\in_array(strtoupper($mysqlType), ['DOUBLE', 'REAL'], true)) {
             $phpstanType = new FloatType();
         }
 
         // fallbacks
         if (null === $phpstanType) {
             switch (strtoupper($mysqlType)) {
+                case 'DECIMAL':
+                case 'NEWDECIMAL':
+                    $phpstanType = new IntersectionType([
+                        new StringType(),
+                        new AccessoryNumericStringType(),
+                    ]);
+                    break;
                 case 'LONGLONG':
                 case 'LONG':
                 case 'SHORT':