Five problems of database operation in commodity supermarket system

Commodity management system , Three tables ,

（ explain ： Commodity list （csb_sp） It's a zipper Watch , Start date （qsrq）、 End date （jsrq） Record the change of sales unit price by date range .）
1、 Inquire about 2021 Since the start of the year , Sales unit price changes of all goods , Display information ： Name of commodity 、 Commodity type 、 Commodity unit 、 Start date 、 End date 、 item pricing .

2、 Inquire about 2021 Warehousing of all goods since the beginning of the year , Display information ： Name of commodity 、 Commodity type 、 Total warehousing 、 Warehousing times 、 Total purchase expenditure . And arrange them in descending order according to the total warehousing amount .

3、 Inquire about 2021 year 3 Commodity transactions in the month , Display information ： Name of commodity 、 Commodity type 、 Total volume of transactions 、 Total transaction amount . In descending order of transaction amount .

4、 Query the transaction volume of cash payment and non cash payment in the first quarter , Display information ： month 、 Number of cash payments 、 Number of non cash payments 、 Proportion of cash payment transaction amount . Arrange in ascending order by month .

5、 The average daily sales volume since the beginning of the year has reached 100 Or the average daily sales will reach 3000 Yuan goods , Display information ： Name of commodity 、 Commodity type 、 Average daily sales 、 Average daily sales .

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Take the answer ：

These problems should be involved in more basic sql knowledge , Don't think too complicated .

Specific code ：

--  problem 1select spmc,splx,spdw,qsrq,jsrq,xsdj from csb_sp where qsrq >= '2021-01-1' ;--  problem 2select b.spmc,b.splx,sum(a.rksl) as  rkzl,count(a.spbh) as rkcs,sum(a.grdj) as zczje  from sp_rkjl aleft join csb_sp b on a.spbh = b.spbh where rkrq >= '2021-01-1' group by b.spmc,b.splx order by sum(a.rksl) desc ;--  problem 3  This needs to consider the change of unit price select b.spmc,b.splx,sum(jysl) as jyzl,sum(a.jysl*b.xsdj) as jyzje from sp_jyjl a left join csb_sp b on a.spbh = b.spbh and a.jyrq between b.qsrq and b.jsrqwhere a.jyrq between '2021-03-01' and '2021-03-31'group by b.spmc,b.splx order by sum(a.jysl*b.xsdj) desc--  problem 4select right(date_format(jyrq, '%Y%m'),2),sum(case when fkfs = 0 then 1 else 0 end ) xjcs,sum(fkfs)  as fxjfkcs  -- be based on fkfs This field is int Type of writing ,sum(case when fkfs = 0 then a.jysl*b.xsdj else 0 end )/sum(a.jysl*b.xsdj) xjfrjyjezb from sp_jyjl a left join csb_sp b on a.spbh = b.spbh and a.jyrq between b.qsrq and b.jsrqwhere  right(date_format(jyrq, '%Y%m'),2) between '01' and '03'group by right(date_format(jyrq, '%Y%m'),2) order by right(date_format(jyrq, '%Y%m'),2) --  problem 5select t1.spmc,t1.splx,avg(jyzl) ,avg(jyzje ) from (select a.jyrq,b.spmc,b.splx,sum(jysl) as jyzl,sum(a.jysl*b.xsdj) as jyzje from sp_jyjl a left join csb_sp b on a.spbh = b.spbh and a.jyrq between b.qsrq and b.jsrqwhere a.jyrq >= '2021-01-01' group by b.spmc,b.splx  ,a.jyrq ) t1 group by t1.spmc,t1.splx having  avg(jyzl) >=100 or avg(jyzje )>=3000

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