where 子句中的表列值

Question

我有兩張桌子

員工

員工ID	姓名	工作
123	大衛	是的
124	提摩太	是的
125	馬克西	不
126	阿比

員工宿舍

ID	員工ID	EmployeeSpclField	EmployeeSpclValue
1	123	已婚	是的
2	123	國籍	墨西哥
3	123	工作	鉗工
4	124	已婚	是的
5	124	國籍	ARG
6	125	工作	司機

我需要一個基於 Bind 值 Employee id 返回 1 或 0 的 Sql 查詢，我需要驗證以下條件

1. 工作不應為空 2）國籍不應為空且他應屬於 MEX

那我該怎么做呢？ 我正在建造這樣的東西

select 1 from Employee emp ,EmployeeResidence er 
where 
employeeid=:empid and emp.job is not null and 

我正在努力包含 EmployeeSpclField 列值來檢查它是否不為 null 並且屬於 MEX

Answer 1

我可能會避免加入，而是在此處使用存在邏輯：

SELECT e.*
FROM Employee e
WHERE Job IS NOT NULL AND
      EXISTS (SELECT 1 FROM EmployeeResidence er
              WHERE er.EmployeeId = e.EmployeeId AND
                    er.EmployeeSpclField = 'Nationality' AND
                    er.EmployeeSpclValue = 'MEX');

Answer 2

選擇一個 0/​​1 標志

select case when exists (
    select 1 
    from Employee emp 
    join EmployeeResidence er 
      on emp.employeeid = er.employeeid and er.EmployeeSpclField = 'Nationality' and er.EmployeeSpclValue = 'MEX'
    where emp.employeeid=:empid and emp.job is not null ) then 1
   else 0 end flag 
from dual;

Answer 3

嘗試這個：

Select
e.EmployeeID,
case when er.EmployeeID is null then 0 else 1 end as return_val
from
Employee e
left outer join
(select EmployeeId,
 max(case when EmployeeSpclField='Married' then EmployeeSpclValue else NULL end) as married,
 max(case when EmployeeSpclField='Nationality' then EmployeeSpclValue else NULL end) as Nationality,
 max(case when EmployeeSpclField='Job' then EmployeeSpclValue else NULL end) as Job
from 
 EmployeeResidence
group by
EmployeeId) er
on e.EmployeeId=er.EmployeeId
and e.Job is not null 
and (er.Nationality is not null and er.Nationality ='MEX')

Answer 4

一種選擇可能是使用條件聚合來計算所需的條件

SELECT SIGN(NVL(SUM(CASE WHEN er.EmployeeSpclField = 'Nationality' 
                          AND er.EmployeeSpclValue = 'MEX' 
                          AND e.Job IS NOT NULL THEN 1 ELSE 0 END),0)) 
    AS Result
  FROM Employee e
  JOIN EmployeeResidence er
    ON er.EmployeeId = e.EmployeeId
 WHERE e.EmployeeId = :empid

其中SIGN()函數是用來考慮可能有重復的記錄Nationality的價值EmployeeSpclField每任何列EmployeeId列的值。

演示