--最大值及其对应时间
select * from waterlevel a where waterlevel = (select max(waterlevel) from waterlevel)
--最小值及其对应时间
select * from waterlevel a where waterlevel = (select min(waterlevel) from waterlevel)
select * from waterlevel a where waterlevel = (select max(waterlevel) from waterlevel)
--最小值及其对应时间
select * from waterlevel a where waterlevel = (select min(waterlevel) from waterlevel)
select * from waterlevel a where NT_ID=62312460 and year(surveytime)=2009 and Month(surveytime)=1 and waterlevel = (select max(waterlevel) from waterlevel)
--最小值及其对应时间
select * from waterlevel a where NT_ID=62312460 and year(surveytime)=2009 and Month(surveytime)=1 and waterlevel = (select min(waterlevel) from waterlevel)补充条件
--最大值及其对应时间
select * from waterlevel a where NT_ID=62312460 and year(surveytime)=2009 and Month(surveytime)=1 and waterlevel = (select max(waterlevel) from waterlevel where NT_ID=62312460 and year(surveytime)=2009 and Month(surveytime)=1)
--最小值及其对应时间
select * from waterlevel a where NT_ID=62312460 and year(surveytime)=2009 and Month(surveytime)=1 and waterlevel = (select min(waterlevel) from waterlevel where NT_ID=62312460 and year(surveytime)=2009 and Month(surveytime)=1)
--最小值及其对应时间
select * from waterlevel a where NT_ID=62312460 and year(surveytime)=2009 and Month(surveytime)=1 and waterlevel = (select min(waterlevel) from waterlevel where NT_ID=62312460 and year(surveytime)=2009 and Month(surveytime)=1)等号旁边有个全角的空格,现在去掉了,再试一下。