运行SQL查询时出现"ORA-00913:值太多"错误

Question

我得到了"太多的值"错误,我不知道如何处理它.问题从第一个嵌套的SELECT开始

SELECT p.name, p.phone_number 
    FROM person p WHERE 
    (SELECT ks.title, ks.ks_code 
    FROM required_skills rs JOIN knowledge_skills ks USING (ks_code) 
    WHERE rs.pos_code = 'CS1') 
    IN (SELECT ks.title, ks.ks_code 
        FROM courses_taken ct  JOIN course_learning_units clu 
        USING (c_code)  JOIN learning_unit_skills lus USING (lu_code) 
        JOIN knowledge_skills ks USING (ks_code))

我查找了有关此错误的信息,我相信这是因为WHERE中的子查询返回了太多列.表格数据如下.但是我该如何减少呢？我感谢任何指点,谢谢

required_skills

POS_CODE    VARCHAR2(10 BYTE)   Yes     1   
KS_CODE VARCHAR2(10 BYTE)   Yes     2   

learning_unit_skills

LU_CODE VARCHAR2(10 BYTE)   Yes     1   
KS_CODE VARCHAR2(10 BYTE)   Yes     2

人

PER_ID  NUMBER(38,0)    No      1   
NAME    VARCHAR2(255 BYTE)  Yes     2   
STREET  VARCHAR2(255 BYTE)  Yes     3   
CITY    VARCHAR2(60 BYTE)   Yes     4   
ZIP_CODE    VARCHAR2(60 BYTE)   Yes     5   
PHONE_NUMBER    VARCHAR2(255 BYTE)  Yes     6   
GENDER  VARCHAR2(6 BYTE)    Yes     7   

课程学习单位

C_CODE  VARCHAR2(10 BYTE)   Yes     1   
LU_CODE VARCHAR2(10 BYTE)   Yes     

课程

C_CODE  VARCHAR2(10 BYTE)   Yes     1   
PER_ID  NUMBER(38,0)    Yes     2   

Answer 1

快速重写:

SELECT p.name, p.phone_number 
    FROM person p WHERE EXISTS
    (SELECT * 
    FROM required_skills rs JOIN knowledge_skills ks USING (ks_code) 
    WHERE rs.pos_code = 'CS1'
      AND (ks.title, ks.ks_code)
    IN (SELECT ks.title, ks.ks_code 
        FROM courses_taken ct  JOIN course_learning_units clu 
        USING (c_code)  JOIN learning_unit_skills lus USING (lu_code) 
        JOIN knowledge_skills ks USING (ks_code))
    )

或(连接可能需要更正):

SELECT p.name, p.phone_number 
    FROM person p WHERE EXISTS
    (SELECT * 
     FROM required_skills rs JOIN knowledge_skills ks USING (ks_code) 
        JOIN ( courses_taken ct  JOIN course_learning_units clu 
               USING (c_code)  JOIN learning_unit_skills lus USING (lu_code) 
              ) USING (ks_code)
     WHERE rs.pos_code = 'CS1'
    )

问题是你的代码与表没有任何关系person.我想你应该在子查询中有一个 - 使它们相关.