I want to do a query like
select * from chr2;
but only have MySQL return the first tuple (or an arbitrary) tuple instead of all of them.
How do I do it?
Use the LIMIT
clause:
SELECT * FROM chr2 LIMIT 1;
If you want an arbitrary row returned, you have to sort your rows by an random col like this ( MySQL docu ):
SELECT * FROM chr2
ORDER BY RAND()
LIMIT 1;
On large tables, however, you might run into performance problems with this, as there a random value has to be created for each row and the table has to be sorted according to this column.
尝试这个 ::
select * from chr2 limit 1
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