Question

我有这个查询插入行，使用如下的子查询：

INSERT INTO Lecture_presence_Student (`presence_id`, `Lecture_id`, `Student_id`, `status`) VALUES

(
 (
  SELECT '' as presence_id, Lecture.Lecture_id, CourseEdition_students_Student.Student_id, 'onverwerkt' 
  FROM
    CourseEdition_students_Student 
        INNER JOIN Lecture ON    CourseEdition_students_Student.CourseEdition_id = Lecture.CourseEdition_id



    )       
)

我没理解，子选择查询返回4列，与INSERT查询的编号相同。为什么它会给我错误：

Column count doesn't match value count at row 1

有什么想法吗？

Answer 1

而不是使用INSERT INTO VALUES，请使用INSERT INTO SELECT FROM

INSERT INTO Lecture_presence_Student 
(
    `presence_id`
    , `Lecture_id`
    , `Student_id`
    , `status`
) 
SELECT '' as presence_id
    , Lecture.Lecture_id
    , CourseEdition_students_Student.Student_id
    , 'onverwerkt' 
FROM    CourseEdition_students_Student 
INNER JOIN Lecture 
    ON    CourseEdition_students_Student.CourseEdition_id = Lecture.CourseEdition_id

然后，如果您的查询中有多条记录，则INSERT将有效。

Answer 2

INSERT INTO Lecture_presence_Student (`presence_id`, `Lecture_id`, `Student_id`, `status`) 
SELECT '' as presence_id, Lecture.Lecture_id, CourseEdition_students_Student.Student_id, 'onverwerkt' 
  FROM
    CourseEdition_students_Student 
        INNER JOIN Lecture ON    CourseEdition_students_Student.CourseEdition_id = Lecture.CourseEdition_id

presence_id的空值是多少？

Answer 3

INSERT INTO Lecture_presence_Student (`presence_id`, `Lecture_id`, `Student_id`, `status`) 

SELECT '', Lecture.Lecture_id, CourseEdition_students_Student.Student_id, 'onverwerkt' 
FROM
CourseEdition_students_Student 
    INNER JOIN Lecture ON    CourseEdition_students_Student.CourseEdition_id = Lecture.CourseEdition_id

删除你的＆＃34; VALUES（（））＆＃34;并且别名没有必要。

带子查询的INSERT查询：列计数与第1行的值计数不匹配

3 个答案: