sqlite - Can the LIKE statement be optimized to not do full table scans? -


i want subtree table tree path.

the path column stores strings like:

foo/ foo/bar/ foo/bar/baz/

if try select records start path:

explain query plan select * f path "foo/%"

it tells me table scanned, though path column indexed :(

is there way make use index , not scan table?

i found way achieve want closure table, it's harder maintain , writes extremely slow...

to able use index in sqlite,

  1. the table column must have text affinity, i.e., have type of text or varchar or that; and

  2. the index must declared collate nocase (either directly, or because column has been declared collate nocase):

    > create table f(path text); > create index fi on f(path collate nocase); > explain query plan select * f path 'foo/%'; 0|0|0|search table f using covering index fi (path>? , path<?)

the second restriction removed case_sensitive_like pragma, change behaviour of like. alternatively, 1 use case-sensitive comparison, replacing like 'foo/%' glob 'foo/*'.


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