sql - Query for each element -
i given following database schema
donuts (name: string, price: integer) grocery (no: string, gname: string, mincredit: integer) distributor (dname: string, gno: string, purchaseyear: integer)
for each year (distributor.purchaseyear), grocery "vons" purchased atleast 1 donut, find number of donuts purchased. output set of tuples, indicates year , number of donuts purchased "vons"
i not sure how approach this. tried
select (d.purchaseyear, count(dd.name)) distributor d, donut dd, grocery g g.name = "vons"
this seems give me incorrect output.
assuming have schema below
donuts (gname: string, price: integer, purchaseyear: integer) // record every donut purchased grocery gname in year grocery (gno: string, gname: string, mincredit: integer) // grocery details distributor (dname: string, gno: string, purchaseyear: integer) // distributor details
you can data below query
select g.name , d.purchaseyear , count(do.gname) distributor d join grocery g on g.gno = d.gno join donuts on do.gname = g.gname g.name = 'vons' group g.name, d.purchaseyear
Comments
Post a Comment