寻常工作几条sql语句记录

。。。统计某水电厂某年每个月累计供水量
select 
Month(t2.tm) as time,
SUM(t2.ll) as tll,
t1.stnm as names 
from LL_ZD_DATA t1 
inner join LL_SS_DATA	t2 
on t2.stcd=t1.stcd 
where t2.stcd='00000002' and t2.tm>'2013/01/01 00:00:00' and t2.tm<'2013/12/31 23:59:59'  
group by Month(t2.tm),stnm 
order by Month(t2.tm)
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。。。某站2013年平均水位
select b.stnm, b.stcd ,avg(t1.rz) 年平均水位 from st_stbprp_b b
inner join st_rsvr_r t1 on t1.stcd=b.stcd 
where   t1.stcd='62902700'  and t1.tm>='2013/1/1' and t1.tm<='2014/1/1' 
group by b.stnm, b.stcd
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。。。查询2013年各测站的年平均水位

/**
第一种方式:*/
select b.stnm 测站名称,b.stcd 测站编码,
(select avg(t1.rz)  from st_rsvr_r t1 where t1.stcd=b.stcd and t1.tm>='2013/1/1' and t1.tm<='2014/1/1' ) as 年平均水位
 from st_stbprp_b b 
 
/**
第二种方式:*/
select b.stnm, b.stcd ,avg(t1.rz) 年平均水位 from st_stbprp_b b
inner join st_rsvr_r t1 on t1.stcd=b.stcd 
where   t1.stcd is not null  and t1.tm>='2013/1/1' and t1.tm<='2014/1/1' 
group by b.stnm, b.stcd
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