在where条件中使用连接列

Question

我有以下表格。表格class_students与students表格相关，因为它从那里获取student_id_column数据。examination_data有一列（{ {1}}）从class_student_id_column表class_students列获取数据。

1. student_id_column

  

student_id | student_names

     

1 ........................... ed

     

2 .......................... bravo

     

3 .........................某个名字

1. students

  

class_students_id | student_id_column | class_year

     

1 ................................... 2 .......... .................... 2000

     

2 ................................... 3 .......... .................... 2000

1. class_students

examination_data_id | class_students_id_column | php | jquery |绘制

1 ......................................... 1 .... ............................. 90 ..... 68 ............ 89 1 ......................................... 2 ....... .......................... 64 ..... 89 ............ 99

我想要更新表examination_data并为行执行此操作，我希望我的where语句指向examination_data列。

要做到这一点，我正在尝试这个

student_id

我的更新语句失败，因为表SELECT examination_data.examination_data_id, examination_data.class_students_id_column, class_students.student_id_column, students.student_id, examination_data.php, examination_data.jquery, examination_data.drawing FROM examination_data LEFT JOIN class_students ON (examination_data.class_students_id_column=class_students.class_students_id) LEFT JOIN students ON (students.student_id=class_students.student_id_column) UPDATE examination_data SET examination_data.jquery = 96 WHERE students.student_id = 2; 中没有students.student_id列。我的另一个尝试是

examination_data

但是那很难打砖墙。

这是否可能，或者我必须在 UPDATE examination_data SET examination_data.jquery = l FROM students INNER JOIN ON students.student_id=... WHERE students.student_id = 2; 表中另外有student_id_column吗？

Answer 1

使用子查询：

UPDATE
  examination_data
SET
  jquery = 96
WHERE
  class_students_id_column = (
    SELECT class_students_id FROM class_students WHERE student_id_column = 2
  )

Answer 2

尝试此查询

UPDATE  examination_data  SET examination_data.jquery = 96 WHERE
examination_data.class_students_id_column =(
SELECT class_students_id FROM class_students WHERE student_id_column = 2);