I have a database table questions on a online web server with 2000+ rows and I need to get 6 randomly selected rows. They must be different so that one question is not two times in the list array of 6 questions.
How can I achieve this?
2 Answers
You have a relatively small amount of data, so the simplest method is:
select q.*
from questions q
order by rand()
limit 6;
In this query, the order by takes the longest amount of time. Ordering 2,000 rows might be noticeable. A simple fix is to reduce the number of rows being ordered. One method is:
select q.*
from questions q cross join
(select count(*) as cnt from questions) m
where rand() < 100 / m.cnt
order by rand()
limit 6;
The where selects about 100 rows randomly and then orders those to select 6. You are pretty much guaranteed that the where will always choose at least 6 rows.
select * from table order by rand() limit 6?your query with RAND() LIMIT 10;