腾讯游戏10大经典案例(一):唯一索引上的重复键
某业务合服后在唯一索引键上出现了重复键现象:mysql& select count(RoleGID) from RoleData_0;
+----------------+
| count(RoleGID) |
+----------------+
某业务合服后在唯一索引键上出现了重复键现象:& select count(RoleGID) from RoleData_0;
+----------------+
| count(RoleGID) |
+----------------+
+----------------+
1 row in set (0.00 sec)
mysql& select count(distinct RoleGID) from RoleData_0;
+-------------------------+
| count(distinct RoleGID) |
+-------------------------+
+-------------------------+
1 row in set (0.00 sec)