SQL COUNT Function
The COUNT(column) function returns the number of rows without a NULL value in the
specified column.
Syntax
SELECT COUNT(column) FROM table
|
Example
With this "Persons" Table:
| Name |
Age |
| Hansen, Ola |
34 |
| Svendson, Tove |
45 |
| Pettersen, Kari |
|
This example finds the number of persons with a value in the "Age"
field in the "Persons" table:
SELECT COUNT(Age) FROM Persons |
Result:
The COUNT(column) function is handy for finding columns without a value. Note
that the result is one less than the number of rows in the original table
because one of the persons does not have an age value stored.
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