sql - Count distinct same names -

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i have table have on 100k information.

id        firstname 1           bob 2           bob 3           tom 4           john            5           john 6           john ..          ....

want procedure count how names same, example must :

firstname      count bob              2 tom              1 john             3

please me write it

it's basic sql example, group column + aggregating results

select     firstname, count(*) table1 group firstname

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