SQL数据库中如果列中有某个值,则怎么删除该列

如果是删除含有-1300000.000的行，语句为：
Delete from SystemPowerOff where maxvalue='-1300000.000'
或：
Delete from SystemPowerOff where avgvalue='-1300000.000'
或：
Delete from SystemPowerOff where minvalue='-1300000.000'
如果是删除列，直接执行Alter table SystemPowerOff drop maxvalue/ avgvalue/minvalue。

select * from table where time = to_date('2017','yyyy');

update table_name t set t.a = 0 where t.b = 1001 ;