Submitted by: Artem Kudlaenko (avk)

Is related to QA573

1. Next SIMILAR TO queries return 'false':

SELECT CASE WHEN '1' SIMILAR TO '(1|2){0,}' ESCAPE '\' THEN 'true' else 'false' end
FROM RDB$DATABASE;

SELECT CASE WHEN '1' SIMILAR TO '(1|2){0,1}' ESCAPE '\' THEN 'true' else 'false' end
FROM RDB$DATABASE;

But this query return 'true':

SELECT CASE WHEN '1' SIMILAR TO '(1|2){1}' ESCAPE '\' THEN 'true' else 'false' end
FROM RDB$DATABASE;

2. Next SIMILAR TO query return 'false':

SELECT CASE WHEN '123' SIMILAR TO '(1|12[3]?){1}' ESCAPE '\' THEN 'true' else 'false' end
FROM RDB$DATABASE;

But this query return 'true':

SELECT CASE WHEN '123' SIMILAR TO '(1|12[3]?)+' ESCAPE '\' THEN 'true' else 'false' end
FROM RDB$DATABASE;

Commits: 6820b50

====== Test Details ======

See also test for CORE2006 and samples in core-4740
See also (in russian): http://sql.ru/forum/actualutils.aspx?action=gotomsg&tid=1026749&msg=14380584