Sorry I forget the lower command when I wrote the code, it is like this:
lower(g.country_code) like lower('US')
(lower(g.feature_class) like lowwer('P') or lower(g.feature_class) like
lower('L'))2018-01-16 17:40 GMT+01:00 Martin Moore <martin.mo...@avbrief.com>: > > > >Hi, > > >I have two tables in the same database: geoname and test_table. > > >The geoname table contains many columns which are: name, feature_class, > feature_code, admin1, admin2,admin3, name and so on. > > >The second table 'test_table' contains only the columns: city, state. > > >There is no join between the two tables and I want to make a match > between the data contained in each of them because I need the result for a > farther process. > > >I wrote this query: > > >select g.name, t.city > > >from geoname as g, test_table as t > > >where (lower(g.feature_class) like 'P' or lower(g.feature_class) like 'L') > > >and lower(g.country_code) like 'US' > > >and lower(g.admin1) like lower(t.state) > > >and (lower(g.name) like lower(t.city) or lower(g.name) like lower(t.city > || 'city')) > > >The table geoname contains 370260 rows and the table test_table contains > 10270 rows. > > >The query took a long time to accomplish more than half an hour.Should I > add another column in the table test_table which contains the country_code > and make an inner join with the geoname table or >should I use indexs to > accelerate the process? > > > > Indexes are your friends ☺ > > > > I’d certainly add indexes on lower(g.feature_class, g.country_code) and > lower(t.state) > > > > Note “and lower(g.country_code) like 'US'” will not return any results as > you’ve got the ‘US’ in UPPER…. Same as (lower(g.feature_class) like 'P' or > lower(g.feature_class) like 'L') > > > > Why are you using LIKE? Equals (=) is surely correct and probably faster? > > > > > > Martin. >
