Question

我是Knex.js查询构建器的新手，我目前在某个简单的MySQL选择方面遇到了麻烦。这是：

SELECT orders.*, IFNULL(x.unread, 0) AS unread_messages 
FROM orders
LEFT JOIN
    (SELECT id_order, COUNT(*) AS unread
     FROM chats
     WHERE read_by_user = 0
     GROUP BY id_order) AS x
ON x.id_order = orders.id_order
WHERE id_customer = 42
ORDER BY date_submitted;

我有点失去了阅读Knex的文档，但是我应该使用 .joinRaw 进行连接，使用 knex.raw 进行ifnull命令吗？

Answer 1

https://runkit.com/embed/1olni3l68kn4

knex('orders')
  .select(
    'orders.*', 
    knex.raw('IFNULL(??, 0) as ??', ['x.unread', 'unread_messages'])
  )
  .leftJoin(
    knex('charts')
      .select('id_order', knex.raw('count(*) as ??', ['unread']))
      .where('read_by_use', 0).groupBy('id_order').as('x'), 
    'x.id_order', 
    'orders.id_order'
  )
  .where('id_customer', 42)
  .orderBy('date_submitted')

产生

select 
  `orders`.*, IFNULL(`x`.`unread`, 0) as `unread_messages` 
from `orders` 
left join (
  select `id_order`, count(*) as `unread` 
  from `charts` 
  where `read_by_use` = ? 
  group by `id_order`
) as `x` 
on `x`.`id_order` = `orders`.`id_order` 
where `id_customer` = ? 
order by `date_submitted` asc

Answer 2

对于那些降落在这里的人：在@Mikael的帮助下，这是我的工作解决方案。

getauxval

MySQL上的Knex.js子查询离开了连接

2 个答案: