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i noticed that
(SELECT title, relavency, 'search1' as source FROM search1 ORDER BY relavency DESC LIMIT 10) UNION (SELECT title, relavency, 'search2' as source FROM search2 ORDER BY relavency DESC LIMIT 10) ORDER BY relavency DESC LIMIT 10
the last LIMIT 10 does not work. why?
the error was
"Error code 1064: ... to use near 'LIMIT 1000'"
how come mysql workbench detects LIMIT 10 as LIMIT 1000, but if its 1000 it shld work still?
1000
ORDER BY, LIMIT, and OFFSET Clauses in UNIONEach SELECT statement in a UNION clause can specify its own ORDER BY , LIMIT , and OFFSET clauses. In this case, the SELECT statement must be enclosed by parentheses.
You probably confused “union all” with “cross join”. There are no general limits on SQL statement length, but there can be restrictions in the specific DBMS.
Assume we wish to select all records from 1 - 30 (inclusive) from a table called "Orders". The SQL query would then look like this: $sql = "SELECT * FROM Orders LIMIT 30"; When the SQL query above is run, it will return the first 30 records.
Your query can be rewritten using aliased nested subqueries. This should work for you:
SELECT u.* FROM (
(SELECT s1.title, s1.relavency, 'search1' as source FROM search1 AS s1
ORDER BY s1.relavency DESC
LIMIT 10)
UNION
(SELECT s2.title, s2.relavency, 'search2' as source FROM search2 AS s2
ORDER BY s2.relavency DESC
LIMIT 10)
) AS u ORDER BY u.relavency DESC
LIMIT 10FYI: you misspelled "relevancy" but I preserved the misspelling so the query would work.
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