Question

I have a text column containing URLs that are uniqe.

I need to do a SQL pattern match query, say using the ‘like’ SQL operator.

In such a scenario, will SQLite do a FTS ( Full Table Scan ) regardless of whether I have an index on that column or not ( column is a primary key )?

It seems to be that its doing a FTS as the speed of operation is telling – or is the speed impact due to the ‘like’ query although the column is indexed?

Answer 1

The SQLite Query Planner

4.0 The LIKE optimization

Terms that are composed of the LIKE or
GLOB operator can sometimes be used to
constrain indices. There are many
conditions on this use:

1. The left-hand side of the LIKE or GLOB operator must be the name of
   an indexed column.
2. The right-hand side of the LIKE or GLOB must be a string literal that
   does not begin with a wildcard
   character. […]

Update: by default case_sensitive_like mode is OFF. Turning it ON might make it behave like =.

PRAGMA case_sensitive_like = ON; -- OFF
SELECT * FROM your_table WHERE field LIKE '...'