Not exists 子句未按预期工作

Question

我想搜索没有任何分析师 (cod_role_acces) 为其工作的所有公司 (niu_lds)。

示例：假设有一家公司 X，有 3 名员工。其中一位是分析师。我不希望那家公司出现在我的结果中。但如果 Y 公司有 2 名员工，而且他们都不是“分析师”，那么我希望这家公司出现在结果中。

这是我的查询：

SELECT DISTINCT
    a.name_pers as "First Name",
    a.last_pers as "Last Name",
    a.id as "# account",
    a.cod_role_acces as "Profile", 
    a.niu_lds as "Company", 
    b.cod_missn as "Mission", 
    
FROM sr.c_r_v_obt_cp_util a inner join ods.c_od_missn_ld b on a.niu_lds = b.niu_lds

WHERE a.cod_eta_util in ('VER', 'APPR')
and a.id_cod_sr_alim = '2'
and b.cod_missn = 'PHA'

 and not exists (select null
                 from sr.c_r_v_obt_cp_util c 
                 where c.niu_lds = a.niu_lds
                 and a.cod_role_acces = 'ANALYST'
                );

我的问题是它让我拥有“分析师”的“公司”！我想查看所有没有归属于该公司的 'ANALYST'(cod_role_access) 的公司 (niu_lds)。

我已经问过这个问题，有人帮了我很多，但我仍然没有得到预期的输出。

我的第一个问题：SQL query to check if a value isn't present

谢谢

Answer 1

我相信 Romeo 将 null 更改为 1 的答案可能会让你到达那里。

如果没有，并且您想直观地查看发生了什么比较，您可以将 not exists 函数转换为左连接，这样您就可以看到值的放置位置。

使用上一篇文章中的测试示例 -

with test (company, ename, profile) as
      (select 'BMW', 'Scott', 'Analyst' union all
       select 'BMW', 'King' , 'Manager' union all
      select 'BMW', 'Mike' , 'Clerk'  union all
      select 'SAP', 'John' , 'Clerk' union all
      select 'SAP', 'Fred' , 'Manager' 
    )
  select a.company, a.ename, a.profile, b.analyst
  from test a
  left join (select 1 as analyst, company
        from test
        where profile = 'Analyst') b
        on b.company = a.company

以下是返回-

COMPANY	ENAME	PROFILE	ANALYST
BMW	Scott	Analyst	1
BMW	King	Manager	1
BMW	Mike	Clerk	1
SAP	John	Clerk	null
SAP	Fred	Manager	null

您可以从这里看到所有 BMW 都被标记为 Analyst，如果您想构建左连接而不是不存在但“隐藏”标记为 Analyst 的列，请添加“其中 b.analyst 为空”并从 select 语句中删除 b.analyst -

with test (company, ename, profile) as
      (select 'BMW', 'Scott', 'Analyst' union all
       select 'BMW', 'King' , 'Manager' union all
      select 'BMW', 'Mike' , 'Clerk'  union all
      select 'SAP', 'John' , 'Clerk' union all
      select 'SAP', 'Fred' , 'Manager' 
    )
  select a.company, a.ename, a.profile
  from test a
  left join (select 1 as analyst, company
        from test
        where profile = 'Analyst') b
        on b.company = a.company
where b.analyst is null

这将返回预期的表 -

COMPANY	ENAME	PROFILE
SAP	John	Clerk
SAP	Fred	Manager

编辑添加了 OP 的等价物：

这些应该与最初发布的逻辑和您的代码相匹配 -

存在 AnalystFlag -

SELECT DISTINCT
    a.name_pers as "First Name",
    a.last_pers as "Last Name",
    a.id as "# account",
    a.cod_role_acces as "Profile", 
    a.niu_lds as "Company", 
    b.cod_missn as "Mission", 
    c.analyst as "AnalystFlag"
    
FROM sr.c_r_v_obt_cp_util a 
  inner join ods.c_od_missn_ld b 
    on a.niu_lds = b.niu_lds
  left join (select distinct 1 as analyst, niu_lds
                 from sr.c_r_v_obt_cp_util
                 where cod_role_acces = 'ANALYST') c
                 on a.niu_lds = c.niu_lds

WHERE a.cod_eta_util in ('VER', 'APPR')
and a.id_cod_sr_alim = '2'
and b.cod_missn = 'PHA'
;

移除 AnalystFlag -

SELECT DISTINCT
    a.name_pers as "First Name",
    a.last_pers as "Last Name",
    a.id as "# account",
    a.cod_role_acces as "Profile", 
    a.niu_lds as "Company", 
    b.cod_missn as "Mission", 
    
FROM sr.c_r_v_obt_cp_util a 
  inner join ods.c_od_missn_ld b 
    on a.niu_lds = b.niu_lds
  left join (select distinct 1 as analyst, niu_lds
                 from sr.c_r_v_obt_cp_util
                 where cod_role_acces = 'ANALYST') c
                 on a.niu_lds = c.niu_lds

WHERE a.cod_eta_util in ('VER', 'APPR')
and a.id_cod_sr_alim = '2'
and b.cod_missn = 'PHA'
and c.analyst IS NULL
;