Mysql join three tables (2 of them similar) - mysql

Question

my customer table
id | name
==========
1 | mick
2 | george
3 | john
bakery transactions
id | customer | type | amount | date
============================================
1 | 3 | bread | 1 | 2016/03/10 10:00
2 | 1 | bread | 2 | 2016/03/10 11:00
3 | 1 | baguette| 1 | 2016/03/10 11:00
4 | 2 | bread | 2 | 2016/03/11 09:00
5 | 3 | cookie | 5 | 2016/03/11 09:30
greengrocery transactions
id | customer | type | amount | date
============================================
1 | 1 | banana | 1 | 2016/03/10 08:00
2 | 1 | apple | 3 | 2016/03/10 08:00
3 | 1 | orange | 5 | 2016/03/10 14:00
4 | 3 | apple | 8 | 2016/03/11 09:30
5 | 1 | apple | 8 | 2016/03/12 09:30
Is it possible to get customer transactions by date from these transaction tables by the customer?
More specific, I want to get customer Id:1 transactions, ordered by date;
This is what I want.
Id| transactionType|customer | type | amount | date
=====================================================================
1 | greengrocery | 1 | banana | 1 | 2016/03/10 08:00
2 | greengrocery | 1 | apple | 3 | 2016/03/10 08:00
2 | bakery | 1 | bread | 2 | 2016/03/10 11:00
3 | bakery | 1 | baguette| 2 | 2016/03/10 11:00
4 | greengrocery | 1 | orange | 5 | 2016/03/10 14:00
5 | greengrocery | 1 | apple | 8 | 2016/03/12 09:30

Answer 1

You basically need two joined queries unioned together, like this:
SELECT * FROM (
SELECT t.id,'bakery' as TransType,s.id as customer,t.type,t.amount,t.date
FROM customer s
INNER JOIN bakery t ON(s.id = t.customer)
UNION ALL
SELECT t.id,'greengrocery' as TransType,s.id as customer,t.type,t.amount,t.date
FROM customer s
INNER JOIN greengrocery t ON(s.id = t.customer)) tt
WHERE tt.customer = 1
order by tt.date
Basically, you don't even need to select from customer because your are not using the name value, so it can be done like this:
SELECT * FROM (
SELECT t.id,'bakery' as TransType,t.customer as customer,t.type,t.amount,t.date
FROM bakery t
UNION ALL
SELECT t.id,'greengrocery' as TransType,t.customer as customer,t.type,t.amount,t.date
FROM greengrocery t) tt
WHERE tt.customer = 1
order by tt.date

Answer 2

You'd be better off having one table for transactions with a category field
id | category_id | customer | type | amount | date
============================================
1 | 1 | 3 | bread | 1 | 2016/03/10 10:00
And then a category table like:
id | category_name |
====================
1 | bakery
You can then do a join like so:
SELECT transactions.id, category_name AS transactionType, customer.name, transactions.type, tranasactions.amount, transactions.date
FROM transactions
LEFT JOIN categories ON transactions.category_id=categories.id
LEFT JOIN customers ON transactions.customer=customer.id

Answer 3

Use UNION ALL to generate the rows and use a variable to generate the new id.
SET #id = 0;
( SELECT #id:=#id+1 id, 'bakery', customer, type, amount, date
FROM bakery_transactions
WHERE customer = 1 )
UNION ALL
( SELECT #id:=#id+1 id, 'greengrocery', customer, type, amount, date
FROM greengrocery_transactions
WHERE customer = 1 )
ORDER BY date