TYPO3 Core

Try the following:

• create a file ext_tables_static+adt.sql in the root of an extension
• it should be imported when the extension ist loaded the first time
• more information here: https://docs.typo3.org/m/typo3/reference-coreapi/main/en-us/ExtensionArchitecture/FileStructure/ExtTablesStaticAdtSql.html

It works when the file contains only the following comment styles:

# single line comment
-- single line comment

It does not work with comment styles like this:

/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
/*!40103 SET TIME_ZONE='+00:00' */;
/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;

/*!40000 ALTER TABLE `tx_mytable` DISABLE KEYS */;

In this case every line after the first appearence of /* is dropped. The reason lies in these code:

sysext/core/Classes/Database/Schema/SqlReader.php, line 99 - 112:

  // recognizes the beginning of a multiline comment
  if (strpos($lineContent, '/*') === 0 && substr($lineContent, -2) !== '*/') {
    $isInMultilineComment = true;
  }
  // should recognize the ending of a mulitline comment but doesn't because 
  // the */ is not on expected position -2. Perhaps it would be sufficent to ask
  // if */ is anywhere in the line: strpos($lineContent, '*/') !== 0
  if (substr($lineContent, -2) === '*/') {
    $isInMultilineComment = false;
  }

In my tries it was sufficient to change the line

(substr($lineContent, -2) === '*/') {

to

(strpos($lineContent, '*/') !== 0) {