Question

Ive been trying to get sqlite to use an index with a like to no avail. Ive tried collate nocase and still no luck. Anyone have any ideas on how to get sqlite to do a like hitting an index. Thanks in advance

DROP TABLE IF EXISTS "test";
DROP TABLE IF EXISTS "test2";
DROP TABLE IF EXISTS "test3";
create table test(name TEXT COLLATE NOCASE);
create table test2(name TEXT);
create table test3(name TEXT);
create index idx_test_name on test(name);
create index idx_test2_name on test2(name);
create index idx_test3_name on test3(name COLLATE NOCASE);
insert into test(name) values('dan');
insert into test2(name) values('dan');
insert into test3(name) values('dan');
--explain query plan select * from test where name like 'test%' 
-- explain query plan select * from test2 where name like 'test%' 
-- explain query plan select * from test3 where name like 'test%' 

Answer 1

In SQLite 3.6.23.1, the index on test is used:

> explain query plan select * from test where name like 'test%';
TABLE test WITH INDEX idx_test_name

> explain query plan select * from test2 where name like 'test%';
TABLE test2

> explain query plan select * from test3 where name like 'test%';
TABLE test3

With a development version of SQLite 3.7.15, both test‘s and test3‘s indexes are used (the index on test2 is used for scanning, not searching):

> explain query plan select * from test where name like 'test%';
SEARCH TABLE test USING COVERING INDEX idx_test_name (name>? AND name<?) (~31250 rows)

> explain query plan select * from test2 where name like 'test%';
SCAN TABLE test2 USING COVERING INDEX idx_test2_name (~500000 rows)

> explain query plan select * from test3 where name like 'test%';
SEARCH TABLE test3 USING COVERING INDEX idx_test3_name (name>? AND name<?) (~31250 rows)

So the answer is to update SQLite.