SQL Query to Retrieve data by comparing column name to a particular string

Question

I have a SQL Table consisting of customer, transaction and store. Store has 3 values (X,Y,Z)

I want to retrieve customers who shopped at particular store, so I used this query

select distinct customer from TABLE group by store.

However, now I want the customer details who shopped at 2 stores (X,Y) (Y,Z) (Z,X) and also (X,Y,Z).

When I use

select distinct customer from TABLE where store='X' 

it gives 0 results in oracle SQL Developer

How to proceed from here?

Answer 1

Try following:

   Select Customer From
    (
         Select Customer,Store from TableName group by Store,Customer
    )tbl
    Group By Customer Having COUNT(Customer)>=2 Order By Customer

Edit:

Declare @MainTable table
(
  Customer varchar(222),Store varchar(2222)
)
Insert Into @MainTable
Select 'C1','X'
Union All
Select 'C1','Y'
Union All
Select 'C1','X'
Union All
Select 'C2','X'
Union All
Select 'C2','Y'
Union All
Select 'C2','Z'
Union All
Select 'C3','X'
Union All
Select 'C3','Z'
Union All
Select 'C4','X'
Union All
Select 'C4','Y'


Declare @temp table 
(
  Customer varchar(200)
)
Insert Into @temp 
Select Customer From
    (
         Select Customer,Store from @MainTable group by Store,Customer
    )tbl
Group By Customer Having COUNT(Customer)>=2 Order By Customer


Declare @Customer_Store table 
(
  Customer varchar(200),
  Stores varchar(200)
)

DECLARE @Stores varchar(10)
Declare @Customer varchar(256)
While((Select COUNT(*) From @temp)>0)
Begin
        Set @Customer=(Select Top 1 Customer From @temp)
        Select @Stores=coalesce(@Stores + ',','') + Store From 
        @MainTable Where Customer=@Customer
        Group By Store
        Order By Store

        Insert Into @Customer_Store Select @Customer,@Stores

        Delete From @temp Where Customer=@Customer
        Set @Stores=null
End


Select Cast(COUNT(Customer) as Varchar(5))+' Customers shopped at Store ('+Stores+')'          CustomerDetail From @Customer_Store
Group By Stores

Output:

2 Customers shopped at Store (X,Y)
1 Customers shopped at Store (X,Y,Z)
1 Customers shopped at Store (X,Z)

Answer 2

select distinct customer from tablename group by customer ,store having count(stores)>2

sorry....you can try like this

"select customer,store from table_name group by customer ,store having count(customer)>=1 order by customer asc"

i hope this is correct.

Answer 3

I think you should use something like GROUP_CONCAT in MySQL.

Here you can find how you can emulate it in Oracle

For example for Oracle 11g R2 you can use LISTAGG:

SQLFiddle demo

SELECT customer, 
       LISTAGG(store, ',') WITHIN GROUP (ORDER BY store) 
       AS STORES
FROM   
(select distinct customer,store from t) t1
GROUP BY customer;