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MySQL:
SELECT column from table
ORDER BY RAND()
LIMIT 1
PostgreSQL:
SELECT column from table
ORDER BY RANDOM()
LIMIT 1
Microsoft SQL Server:
SELECT TOP 1 column from table
ORDER BY NEWID()
IBM DB2
SELECT column, RAND() as IDX
from table
ORDER BY IDX FETCH FIRST 1 ROWS ONLY
Thanks Tim
Oracle:
SELECT column from
( SELECT column from table
ORDER BY dbms_random.value )
WHERE rownum = 1
Thanks Mark Murphy
Feel free to post other example, variations, and SQL statements for other database servers in the comments.


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select 2|8       --10
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