left join in mysql query syntax error..

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i hv 3 tables..

1.tbl_course

SQL

id name
-------
1 | MCA
2 | MBA
3 | BSc
4 | MSC

2.tbl_branch

SQL

branch_id | course_id | branch_name
------------------------------------
1         |   2         |HR
2         |   2         |FINANCE
3         |   2         |MARKTING
4         |   3         |COMPUTER SCNCE
5         |   4         |ENGLISH

3.table_subjects

SQL

subject_id|course_id|branch_id|subject_name
-------------------------------------------
1         |   2     | 1       |SUB1
2         |   2     | 2       |SUB2
3         |   3     | 4       |SUB3

the table_subject fields are based on foriegnkey concept
how can i add values of table_course value MCA to table subject.
it doesnot have a branch so branch id is null.

but also i need a result like

SQL

course_name|Branch_name|subject_name
-------------------------------------------------
 MCA       |           |
 MBA       |     HR    |   SUB1 
 MBA       |   FINANCE |   SUB2

how can i achieve this... any idea???

Posted 17-Jun-13 3:45am

sabodh

Updated 17-Jun-13 4:10am

gvprabu

v2

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Comments

Prasad Khandekar 17-Jun-13 10:03am

If you have set up foreign keys on the subject table then you can not insert a row with foreign key column as null value. For this to work. Don't setup foreign key relation with other tables on table_subjects. You will then have to programmatically enforce that.

Any way the query to retrieve the desired result will be

SELECT c.name, b.name, s.name
FROM subject s
LEFT JOIN tbl_course c ON c.id = s.course_id
LEFT JOIN tbl_branch b ON b.branch_id = s.branch_id

CHill60 17-Jun-13 18:03pm

Next time post the code that created the "syntax error" of the title, as well as full details of the error

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