COUNT has actually two forms: COUNT(*) counts the number of rows in a table; and COUNT(expr) counts the non-null occurrences of expr. This is very useful for generating reports, e.g.:
SELECT COUNT(*) AS ‘Total’, COUNT(ID_winner) AS ‘Claimed’
COUNT has actually two forms: COUNT(*) counts the number of rows in a table; and COUNT(expr) counts the non-null occurrences of expr. This is very useful for generating reports, e.g.:
SELECT COUNT(*) AS ‘Total’, COUNT(ID_winner) AS ‘Claimed’
