想要将第二个查询的列连接到第一个查询但出现 "query block has incorrect number of result columns" 等错误

Question

SELECT
    ID, PRIM_EMAIL, SEC_EMAIL, PHONE 
FROM
    STUDENTS.RECORDS
WHERE 
    ID IN (SELECT ID FROM STUDENTS.INFO WHERE ROLL_NO = '554')

UNION

SELECT NAME 
FROM STUDENTS.INFO 
WHERE ROLL_NO = '554';

这里 Roll_No 是用户插入的数据，所以现在我已经对其进行了硬编码。基本上在 ROLL_NO 的帮助下，我从获得 ID 的地方对 STUDENTS_INFO table 进行排序，并在此基础上尝试获得 PRIM_EMAIL、SEC_EMAIL, PHONE 来自 STUDENTS.RECORDS table 同时匹配两个 table 的外键。除了当前结果集，我还想要 prov_name 列。

非常感谢任何帮助。谢谢！

Answer 1

我怀疑您想将所有这些信息放在同一行，这表明 join 而不是 union all:

select 
    r.ID,
    r.PRIM_EMAIL, 
    r.SEC_EMAIL,
    r.PHONE,
    r.NAME
from STUDENTS.RECORDS r
inner join STUDENTS.INFO i ON i.ID = r.ID
where I.ROLL_NO = '554';

Answer 2

我认为您的错误 query block has incorrect number of result columns 的根源在于尝试将具有 4 列 (id, prim_email, sec_email, phone) 和 1 列 (name) 的 table 合并在一起.

根据你的问题，我了解到你想要 students.records 的 id, prim_email, sec_email, phone 和 students.info 的 name 中的单个 table。

我认为以下使用 CTE 的查询可能会让您（部分）获得最终结果。您可能需要重构以优化性能。

with s_records as ( select * from students.records ),

s_info as ( select * from students.info ),

joined as ( 

  select
    s_records.id,
    s_records.prim_email,
    s_records.sec_email,
    s_records.phone,
    s_info.name

  from s_records

  left join s_info 
       on s_records.roll_no = s_info.roll_no

  where roll_np = '554' )

select * from joined

总的来说，我认为 join 将成为您解决方案的一部分，而不是 union :-)

想要将第二个查询的列连接到第一个查询但出现 "query block has incorrect number of result columns" 等错误

Want to concatenate column of the second query to the first query but getting errors such as "query block has incorrect number of result columns"

sql

database

oracle

join

subquery