Using PHP, I have a simple database that may store multiple items with the same content. I want to delete the first occurrence of an instance when I use DELETE.
How
You cannot enable these options from within PHP, you need to compile SQLite yourself in order to enable these options. Importantly, you need to download the full version, not the amalgamation source release from SQLite download page.
If you're on Unix, get the sqlite-3.6.20.tar.gz
tarball and download it. Then:
tar xzf sqlite-3.6.20.tar.gz
cd sqlite-3.6.20
export CFLAGS='-DSQLITE_ENABLE_UPDATE_DELETE_LIMIT=1'
./configure
make
Then you'll have the sqlite3
command-line utility and the library files in the .libs
subdirectory.
From here, it seems that you have to compile the SQLite source code using
#define SQLITE_ENABLE_UPDATE_DELETE_LIMIT
in order to enable it.
You can use limit with select and you can combine select and delete like:
DELETE FROM Foo
WHERE someColumn in
(
SELECT someColumn FROM FOO WHERE SomeCondition LIMIT 200
)
DELETE FROM table WHERE rowid = (SELECT rowid FROM table WHERE condition LIMIT 1 )