问题
I have a the following query in PostgreSQL:
SELECT sale_order.id,sale_order.name AS orden, now()::date AS hoy,
sale_order.create_date::date, split_part(res_partner.name,' ',1) AS cliente,
res_partner.email,sale_order.amount_total,res_currency.name FROM
sale_order,product_pricelist,res_currency,res_partner WHERE
sale_order.partner_id = res_partner.id
AND sale_order.pricelist_id = product_pricelist.id
AND product_pricelist.currency_id = res_currency.id
AND sale_order.state = 'sent'
ORDER BY sale_order.create_date DESC;
and the resulting set is looks like this:
658, SO658, 2015-05-17, 2015-04-16, Alejandro, some@email.com, 14272.00, MXN
654, SO654, 2015-05-17, 2015-04-15, Edgar, one@email.com, 4994.96, MXN
653, SO653, 2015-05-17, 2015-04-15, Edgar, one@email.com, 3007.29, USD
As you can see, the 2nd and 3rd records are somehow duplicated, somehow because its the same user but has different id, order name, dates, etc.
How I would like to do is disregard the dates and amounts but GROUP_CONCAT the order names, so the end result would look like this:
SO658, Alejandro, some@email.com
SO653 & SO654, Edgar, one@email.com
As you can see, I dropped the unnecessary columns and GROUP_CONCAT the order names that belongs to the same user so in the end each user would have only one record showing all their order names.
How can I do this in PostgreSQL?
Thank you!
回答1:
It is a bit hard trying out a query without table definitions or an SQL fiddle, but :
You can GROUP BY both cliente and email and then use array_agg, which will return an ARRAY. You can use string_agg(sale_order.name, ' & ') if you want really want a string, but arrays are usually easier to work with.
SELECT array_agg(sale_order.name) AS orden,
split_part(res_partner.name,' ',1) AS cliente,
res_partner.email
FROM sale_order,product_pricelist,res_currency,res_partner
WHERE sale_order.partner_id = res_partner.id
AND sale_order.pricelist_id = product_pricelist.id
AND product_pricelist.currency_id = res_currency.id
AND sale_order.state = 'sent'
GROUP BY cliente, email;
来源：https://stackoverflow.com/questions/30286435/group-concat-for-similar-records-in-postgresql