COUNT
COUNT(f) | ||
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Engine | OK | Alternative |
ingres | Yes | |
mysql | Yes | |
oracle | Yes | |
postgres | Yes | |
sqlserver | Yes |
COUNT
COUNT(column_name) finds the number of non-null values in a column. COUNT(*) also counts the null values.
COUNT is an aggregate function it is normally used with GROUP BY.
SELECT region, COUNT(name) FROM bbc GROUP BY region
With a GROUP BY region
statement each region shows up just once. The COUNT column gives the number of countries for each region.
SELECT region, COUNT(name)
FROM bbc
GROUP BY region
See also
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