An easy test showing just top of the iceberg:
- Create a page with a space in title in a namespace that supports subpages (e.g. User).
- Create a subpage for it.
- Click on former page's move tab. You'll see "This page has no subpages" at the bottom of the dialog instead of subpage(s).
This is because SQLite requires an implicit ESCAPE, for example, if you would like to find all values that end with "100_%", you'll have to write something like:
SELECT * FROM table WHERE field LIKE "%100\_\%" ESCAPE '\'
Therefore, every query that uses LIKE must be appended with ESCAPE for databases that require it.