Question

I have one DB (programming is with Delphi) , and I want to count an item in one column.

For example, the table like this:

column1    | column2
-----------+-------------
employee1  | employee2
employee3  | employee1
employee1  | employee1
employee2  | employee3

I want to count employees in that columns, for example, how i can get result 2, from count( employee1) in column1?

Answer 1

A standard SQL aggregate that can be used in all database engines.

This gives “count per employee value”

SELECT
   column1, COUNT(*)
FROM
   MyTable
GROUP BY
   column1

For employee1 only

SELECT
   COUNT(*)
FROM
   MyTable
WHERE
   column1 = 'employee1'