 复制mysql> select count(*) from no_part_tab where -> c3 > date ‘1995-01-01′ and 通过n提c3 < date ‘1995-12-31′; +———-+ | count(*) | +———-+ | 795181 | +———-+ 1 row in set (38.30 sec) mysql> select count(*) from part_tab where -> c3 > date ‘1995-01-01′ and c3 < date ‘1995-12-31′; +———-+ | count(*) | +———-+ | 795181 | +———-+ 1 row in set (3.88 sec) mysql> explain select count(*) from no_part_tab where -> c3 > date ‘1995-01-01′ and c3 < date ‘1995-12-31′\G |