mysql - 如何在 select 语句中使用嵌套 select 执行计数

Question

所以问题来了。我正在尝试编写一份新的填充率报告，因为内置的报告不够好...我正在尝试运行单个 select 语句来返回两者，即特定月份订购某商品的次数的计数，然后还统计已开具发票/全额发货的次数。

这段代码显然是错误的，我目前也将其限制为只能查看 2015 年 8 月的数据，但这只是为了简化测试过程中的结果。

我不知道如何进行第二次计数...这就是我正在尝试的(大脑卡在旧的每个循环逻辑上):

select inv_mast.item_id, 
       inv_mast.item_desc,
       "YEAR" = year(oe_line.required_date), 
       "MONTH" = month(oe_line.required_date),
       "ORDERS" = count(1),
       "HITS" = (
                  select count(1)
                  from invoice_line
                where invoice_line.order_no = oe_line.order_no 
                  and invoice_line.oe_line_number = oe_line.line_no
                  and invoice_line.qty_shipped = oe_line.qty_ordered
               )            


from oe_line, 
     inv_mast,
     inv_loc

where inv_mast.inv_mast_uid = oe_line.inv_mast_uid 
  and inv_mast.delete_flag = 'N'
  and inv_mast.inv_mast_uid = inv_loc.inv_mast_uid
  and inv_loc.location_id = '101'

  and year(oe_line.required_date) = '2015' 
  and month(oe_line.required_date) = '8'


group by inv_mast.item_id, 
         inv_mast.item_desc,
         year(oe_line.required_date), 
         month(oe_line.required_date)

order by inv_mast.item_id

Answer 1

对我来说，您似乎可以重写查询以使用发票行表上的左联接。没有任何适当的测试数据我不能保证它是正确的，但我认为应该是正确的。

除了左连接之外，我还更改为显式连接并移动了别名，因为我认为 MySQL 不支持 alias = column 语法。

select inv_mast.item_id, 
       inv_mast.item_desc,
       year(o.required_date) as "YEAR", 
       month(o.required_date) as "MONTH",
       count(1) as "ORDERS",
       count(invoice_line.order_no) as "HITS"
from oe_line o
join inv_mast on inv_mast.inv_mast_uid = o.inv_mast_uid 
join inv_loc  on inv_mast.inv_mast_uid = inv_loc.inv_mast_uid
left join invoice_line on invoice_line.order_no = o.order_no 
                      and invoice_line.oe_line_number = o.line_no
                      and invoice_line.qty_shipped = o.qty_ordered
where inv_mast.delete_flag = 'N'
  and inv_loc.location_id = '101'
  and year(o.required_date) = '2015' 
  and month(o.required_date) = '8'

group by inv_mast.item_id, 
         inv_mast.item_desc,
         year(o.required_date), 
         month(o.required_date)

order by inv_mast.item_id;