使用like运算符进行内部联接SQL

Question

I have my main table that has a column for a search query. A simplified example:

Querytable

id   query
1    hello new york
2    no information here
3    madison festival 

Geotable

id   suburb     postcode
11    new york   123
12    brooklyn   345
13    madison    999

If the search query has a location, I want to retrieve the postcode in a sample result as follows:

id     query             suburb      postcode
1      hello new york    new york    123
3      madison festival  madison     999

I'm at the moment doing this via SQL and returns the desired result (almost: with errors like if `inform' is a suburb it will be retrieved although we want to match full words).

SELECT QT.id, query, suburb, postocde
FROM Querytable as QT
INNER JOIN Geotable ON query LIKE concat('%',suburb,'%');

Since the above tables are large how can I improve this query? Or is there a better way to tackle this problem?

Answer 1

from your table, i think the JOIN should be on column ID and your LIKE should be in WHERE, not in JOIN. so something like this instead

SELECT QT.id, query, suburb, postocde
FROM Querytable as QT
INNER JOIN Geotable GT ON QT.id=GT.id 
WHERE query LIKE concat('%',suburb,'%');

but even with that, if `inform' is a suburb it will be retrieved since it match the like '%inform%' condition. do you have index in that table to improve performance? in which column you put the indexes?

Answer 2

I did some changes in your query and gives the desired result for me. Try this.

SELECT QT.id, query, suburb, postcode
FROM Querytable as QT
INNER JOIN Geotable ON concat(query,Space(1)) LIKE concat('%',suburb,'[ ]%')