如何在PostgreSQL中使用uniq命令

Question

如何使用order和uniq？

auction.invoices.get_auction_invoices.item_invoices. 
joins("INNER JOIN users ON users.id = invoices.usable_id").order("users.first_name").uniq 

上面的查詢給我下面的錯誤：

這是我的範圍

範圍：item_invoices， - > {加入（：invoice_details）。凡（ 「？invoice_details.invoiceable_type =」， 「項」）}

範圍：get_auction_invoices， - > {其中（：ID =>（item_invoices.skip_cancelled_invoice + donators.skip_cancelled_invoice））}

PG::InvalidColumnReference: ERROR: for SELECT DISTINCT, ORDER BY expressions must appear in select list LINE 1: ...oice_details.invoiceable_type = 'Item') ORDER BY users.firs... : SELECT DISTINCT "invoices".* FROM "invoices" INNER JOIN "invoice_details" ON "invoice_details"."invoice_id" = "invoices"."id" INNER JOIN users ON users.id = invoices.usable_id WHERE "invoices"."eventable_id" = $1 AND "invoices"."eventable_type" = $2 AND "invoices"."id" IN (1132, 1131, 777, 777, 777, 3013, 3024, 3024, 3024, 3024, 3041, 3041, 3013) AND (invoice_details.invoiceable_type = 'Item') ORDER BY users.first_name

Answer 1

試試這個：

auction.invoices.get_auction_invoices.item_invoices.\ 
select("invoices.*, users.*").\ 
joins("INNER JOIN users ON users.id = invoices.usable_id").\ 
order("users.first_name").\ 
uniq