@stof This is what the [DocBlock](https://github.com/deeky666/dbal/blob/eea570194c04cbecd3157c2e7fe25055b7cb70a8/lib/Doctrine/DBAL/Platforms/AbstractPlatform.php#L721) of the API describes it to work like. Other expression methods work like this, too. I think the reason for this is that you actually do not have to use a literal char but could read the char to trim from a column or expression instead. Like

```sql
SELECT TRIM(LEADING prefix_column FROM string_column) FROM mytable;
```