mysql count column
MySQL – Count Number of Unique Values – Stack Overflow
mysql – How do I count columns of a table – Stack Overflow
MariaDB [guanzhi_removeDuplicate]> SELECT count( DISTINCT(staff_id) ) FROM selection; +—————————–+ | count( DISTINCT(staff_id) ) | +—————————–+ | 279 | +—————————–+ 1 row in set (0.02 sec) MariaDB [guanzhi_removeDuplicate]> |
［总结］
用：
SELECT count( DISTINCT(ColumnName) ) FROM TableName; |
去显示某列的，独一无二，不重复，的个数。
转载请注明：在路上 » ［已解决］MySQL中统计某列的不重复的个数