mysql - Join is not working in MY SQL -
select distinct c.fname, s.description customer c inner join orders o on c.customer_num = o.customer_num inner join items on o.order_num = i.order_num inner join stock s on s.stock_num = i.stock_num i.manu_code = 'anz';
i'm confident join
"working" in mysql.
(i add here example demonstrates works.)
edit
if have 2 or columns "in common" between 2 tables, , want reference both columns in equality comparisons in join predicate, add and col2 = col2
existing on
clause...
for example, add condition cust_id
equal between customer
, orders
select distinct c.fname , s.description customer c join orders o on o.customer_num = c.customer_num , o.cust_id = c.cust_id -- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ add line join items on i.order_num = o.order_num join stock s on s.stock_num = i.stock_num i.manu_code = 'anz';
if want join between customer
, orders
on either customer_num
or cust_id
, can replace and
or
. (but odd pattern, having 2 different columns match on; not normative pattern.)
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