How can I request a random row (or as close to truly random as is possible) in pure SQL?
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Answer
See this post: SQL to Select a random row from a database table. It goes through methods for doing this in MySQL, PostgreSQL, Microsoft SQL Server, IBM DB2 and Oracle (the following is copied from that link):
Select a random row with MySQL:
SELECT column FROM table ORDER BY RAND() LIMIT 1
Select a random row with PostgreSQL:
SELECT column FROM table ORDER BY RANDOM() LIMIT 1
Select a random row with Microsoft SQL Server:
SELECT TOP 1 column FROM table ORDER BY NEWID()
Select a random row with IBM DB2
SELECT column, RAND() as IDX FROM table ORDER BY IDX FETCH FIRST 1 ROWS ONLY
Select a random record with Oracle:
SELECT column FROM ( SELECT column FROM table ORDER BY dbms_random.value ) WHERE rownum = 1