Oracle 将以下查询作为一个查询联接是否可行

能否将以下查询合并到单个查询中

一,

二,

三,

四,

---

如果不知道您的表结构，就很难准确地说出哪种方式会给您带来最好的结果。您可以将查询重写为一个查询，将不同的表连接在一起，但是您从中选择的表似乎完全不同。如果不知道你的桌子设计，很难说这是不是最好的做法

或者，如果您只是希望将结果集合并到单个数据集中，基本上将每个查询的结果合并到单个输出中，那么您可以使用

UNION[ALL]

。您需要确保每个查询的select列表中的列正确匹配/对齐。这并不理想，但它应该能满足你的需求

with combined_results as (
    select a.usr_id as usr_id, 
        a.usr_desc as usr_desc, 
        a.usr_type as usr_type, 
        b.usr_desc as usr_prof_name,
        null as dept_name, 
        null as cur_code,
        0 as min_amt,
        0 as max_amt,
        null as msg_type
    from sc_usr_prof_m a, sc_usr_type_m b 
    where a.usr_type=b.usr_type 
    and a.current_status='A' 
    union all
    select distinct 
        a.usr_id as usr_id, 
        a.usr_desc as usr_desc,
        null as usr_type,
        null as usr_prof_name, 
        b.dept_name as dept_name, 
        null as cur_code,
        0 as min_amt,
        0 as max_amt,
        null as msg_type
    from sc_usr_prof_m a ,sc_user_depts b 
    where a.usr_id=b.usr_id 
    and a.usr_status='E'  
    and a.current_status='A'
    union all
    select a.usr_id as usr_id, 
        a.usr_desc as usr_desc, 
        null as usr_type,
        null as usr_prof_name, 
        null as dept_name,
        b.curr_code as curr_code, 
        b.min_amt as min_amt, 
        b.max_amt as max_amt,
        null as msg_type
    from sc_usr_prof_m a, sc_auth_limit_m b  
    where a.usr_id=b.usr_id 
    and a.usr_status='E'
    and a.current_status='A' 
    and b.max_amt not in ('0') 
    union all
    select a.usr_id as usr_id, 
        a.usr_desc as usr_desc, 
        null as usr_type,
        null as usr_prof_name, 
        null as dept_name,
        null as cur_code,
        0 as min_amt,
        0 as max_amt,
        b.msg_type as msg_type 
    from sc_usr_prof_m a, sc_user_msgs_m b  
    where a.usr_id=b.usr_id 
    and a.usr_status='E' 
    and a.current_status='A' 
    and b.swift_enable='Y'
)
select *
from combined_results 
order by usr_id;

我还建议您写下您的加入：

select a.col1, a.col2, b.col3, b.col4
from my_a_table a
join my_b_table b
on b.col1 = a.col1
where a.col1 = 123;

而不是您当前的操作方式：

select a.col1, a.col2, b.col3, b.col4
from my_a_table a, my_b_table b
where b.col1 = a.col1
and a.col1 = 123;

---

如果不是出于可读性的原因，尤其是在具有多个联接的较大查询中。

欢迎使用SO，我对您的查询进行了格式化，并根据您的标题在正文中添加了一个简单的问题，但您应该在实际的帖子中添加更多内容。如果您给出一个表结构示例、一些示例数据和一个您希望结果数据集看起来像什么的示例，这也会有所帮助。请花点时间通读这一部分。可行的，是的。明智的，也许不是。第一个查询从

sc_usr_prof_m

中过滤一组不同的记录，因此将其与其他查询组合会更改结果集。每个查询都连接到不同的表，这些表除了

usr\u id

之外可能没有公共的连接列，因此将生成笛卡尔乘积。请帮我解决这个问题

select a.usr_id,a.usr_desc,b.msg_type 
from sc_usr_prof_m a, sc_user_msgs_m b  
where a.usr_id=b.usr_id 
and a.usr_status='E' 
and a.current_status='A' 
and b.swift_enable='Y' 
order by a.usr_id;

with combined_results as (
    select a.usr_id as usr_id, 
        a.usr_desc as usr_desc, 
        a.usr_type as usr_type, 
        b.usr_desc as usr_prof_name,
        null as dept_name, 
        null as cur_code,
        0 as min_amt,
        0 as max_amt,
        null as msg_type
    from sc_usr_prof_m a, sc_usr_type_m b 
    where a.usr_type=b.usr_type 
    and a.current_status='A' 
    union all
    select distinct 
        a.usr_id as usr_id, 
        a.usr_desc as usr_desc,
        null as usr_type,
        null as usr_prof_name, 
        b.dept_name as dept_name, 
        null as cur_code,
        0 as min_amt,
        0 as max_amt,
        null as msg_type
    from sc_usr_prof_m a ,sc_user_depts b 
    where a.usr_id=b.usr_id 
    and a.usr_status='E'  
    and a.current_status='A'
    union all
    select a.usr_id as usr_id, 
        a.usr_desc as usr_desc, 
        null as usr_type,
        null as usr_prof_name, 
        null as dept_name,
        b.curr_code as curr_code, 
        b.min_amt as min_amt, 
        b.max_amt as max_amt,
        null as msg_type
    from sc_usr_prof_m a, sc_auth_limit_m b  
    where a.usr_id=b.usr_id 
    and a.usr_status='E'
    and a.current_status='A' 
    and b.max_amt not in ('0') 
    union all
    select a.usr_id as usr_id, 
        a.usr_desc as usr_desc, 
        null as usr_type,
        null as usr_prof_name, 
        null as dept_name,
        null as cur_code,
        0 as min_amt,
        0 as max_amt,
        b.msg_type as msg_type 
    from sc_usr_prof_m a, sc_user_msgs_m b  
    where a.usr_id=b.usr_id 
    and a.usr_status='E' 
    and a.current_status='A' 
    and b.swift_enable='Y'
)
select *
from combined_results 
order by usr_id;

select a.col1, a.col2, b.col3, b.col4
from my_a_table a
join my_b_table b
on b.col1 = a.col1
where a.col1 = 123;

select a.col1, a.col2, b.col3, b.col4
from my_a_table a, my_b_table b
where b.col1 = a.col1
and a.col1 = 123;