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我有一个工作 SQL 语句，用于计算工作日的工资和计数，这里的 SO 成员之一好心地帮我解决了这个问题。然而，问题是结果出来的只有在那个时期工作过的劳动力。我真正想要的是结果必须显示所有劳动（在 tbl_labor 中），无论他是否在那段时间工作。

select
  lab.lb_name,
  max(days),
  sum(prod.pdtn_qty * pdWk.pd_cost / 12) as Total 
from
  tbl_labor as lab,
  tbl_production as prod,
  tbl_pdWk_process as pdwk,

(select pdn2.lb_id, count(pdn2.lb_id) as days from
  (select  lb_id
  from tbl_production  pdn1
  where pdn1.pdtn_date >= #9/5/2012#
  and   pdn1.pdtn_date <= #2012-09-20#
  group by lb_id, pdtn_date ) as pdn2
     group by pdn2.lb_id) as pdn3

where prod.pdtn_date >= #9/5/2012#
and   prod.pdtn_date <= #2012-09-20#
and prod.lb_id = lab.lb_id
and   prod.pd_making_id = pdwk.pd_making_id
and lab.lb_id = pdn3.lb_id
group by lab.lb_name

以下是我的相关表格：

tbl_labor
 lb_id | lb_name  | lb_OT ($/day) | If_social_sec
   1   |  John    |    10         |    yes
   2   |  Mary    |    10         |    no
   3   |  Jane    |    10         |    no

tbl_production 
pdtn_date  | lb_id  | pdtn_qty(pcs) | pd_making_id 
 5/9/12    |   1    |     200       |    12
 5/9/12    |   1    |     40        |    13
 5/9/12    |   2    |     300       |    12
 7/9/12    |   1    |     48        |    13
 13/9/12   |   2    |     220       |    14
 15/9/12   |   1    |     20        |    12
 20/9/12   |   1    |     33        |    14
 21/9/12   |   2    |     55        |    14
 21/9/12   |   1    |     20        |    12

tbl_pdWk_process 
pd_making_id | pd_cost($/dozen) | pd_id 
    12       |     2            |   001
    13       |     5            |   001
    14       |     6            |   002
4

1 回答 1

4

替换旧式连接

from
  tbl_labor as lab,
  tbl_production as prod,
...
where 
  lab.fld1 = prod.fld1

使用较新的 LEFT JOIN 

from
  tbl_labor as lab
  LEFT JOIN tbl_production as prod ON lab.fld1 = prod.fld1
...

编辑：
在您的原始代码中 

from
  tbl_labor as lab,
  tbl_production as prod
...
where ...
prod.lb_id = lab.lb_id
...

在 tbl_production 和 tbl_labor 表之间创建一个内部连接。它需要用更新的样式 LEFT JOIN 替换 

from
  tbl_labor as lab
  LEFT JOIN tbl_production as prod ON lab.lb_id = prod.lb_id
...

您可以在http://www.w3schools.com/sql/sql_join.asp上阅读有关 SQL JOIN 的信息

于 2012-09-26T09:40:18.563 回答