Hello what I'm trying to do is retrieve values from tables but I'm having a problem with forming a correct SQL statement. This is what i have.
$qry_display = "SELECT a.section_id, b.section_id,b.student_id,c.*
FROM tbl_section AS a
LEFT OUTER JOIN tbl_er AS b On a.section_id = b.section_id
LEFT OUTER JOIN tbl_enroll AS c On b.student_id = c.student_id
WHERE b.student_id=c.student_id
AND a.bname='$branch'";
This is my database structure.
tbl_section:
section_id section_name sy adviser_id level
tbl_er:
student_id section_id
tbl_enroll
student_id fname lname
I'm having problems with forming the proper sql statement would appreciate any help on how to do it right. What i want is to show all students Under a given section.
In what table bname belongs? change bname into sectionname. Try this one,
SELECT c.*
FROM tbl_section a
INNER JOIN tbl_er b
on a.section_ID = b.section_ID
INNER JOIN tbl_enroll c
ON b.student_ID = c.student_ID
WHERE a.sectionname = 'sectionNameHere'
Related
How to join two tables that have a common field in third table?
E.g: Table A has RoleId, role description and Table B has AccessId,Access description.Table C has RoleAccessID,roleid, accessid. I need to display role description and their access description.Please let me know how to achieve this.
You can Try this below logic for your purpose-
SELECT A.role_description, B.access_description
FROM TABLE_A A
INNER JOIN TABLE_C C ON A.RoleId = C.RoleId
INNER JOIN TABLE_B B ON C.AccessId = B.AccessId
try this
SELECT
role.RoleID,
role.Role_Description,
ac.AccessId,
ac.Access_Description
FROM tblRole role
INNER JOIN tblRoleAccessInfo rac ON A.RoleId = C.RoleId
INNER JOIN tblAccessInfo ac ON C.AccessId = B.AccessId
I have this inner join query:
select *
from ioa_invoice_line
INNER JOIN ioa_invoice
ON ioa_invoice_line.invo_id = ioa_invoice.id ;
Now, I want to add this condition also in the above inner join that is
where ioa_invoice_line.invo_id =234
Please advise how to add this condition in above query.
As Felix says in his comment you can add it without problems:
select *
from ioa_invoice_line
INNER JOIN ioa_invoice
ON ioa_invoice_line.invo_id = ioa_invoice.id
AND ioa_invoice_line.invo_id = 234
As this is criteria on the first table, you would usually simply add this WHERE clause at the end of your query (before the semicolon of course).
However, you are dealing with an invoice table and its detail table here and the criteria is on the key linking the tables. So for readability, I would swap the tables and name the parent table first and join the child table. That feels more natural:
select *
from ioa_invoice i
join ioa_invoice_line il on il.invo_id = i.id
where i.id = 234;
select * from
ioa_invoice_line il
INNER JOIN ioa_invoice i
ON il.invo_id = i.id
where il.invo_id = 234
This format use as a professional practice
I have a rather complex (well for me) sql query happening and I am having trouble with some concepts.
I have the following sql on a webpage that i am building
SELECT
[dbo].[Enrolment].[_identity], [dbo].[Enrolment].CommencementDate,
[dbo].[Enrolment].CompletionDate, [dbo].[Enrolment].enrolmentDate,
[dbo].[Course].name coursename, [dbo].[Course].Identifier as QUALcode,
[dbo].[Person].givenName, [dbo].[Person].Surname,[dbo].[Employer].name as empname,
[dbo].[Employer].Address1,[dbo].[Employer].Suburb,[dbo].[Employer].Phone,
[dbo].[Employer].PostCode,[dbo].[EnrolmentStatus].name as enrolname,
[dbo].[Student].identifier,[dbo].[Student].person,[dbo].[Contact].person as CONTACTid
FROM
(((([dbo].[Enrolment]
LEFT JOIN
[dbo].[Course] ON [dbo].[Enrolment].course = [dbo].[Course].[_identity])
LEFT JOIN
[dbo].[Employer] ON [dbo].[Enrolment].employer = [dbo].[Employer].[_identity])
LEFT JOIN
[dbo].[EnrolmentStatus] ON [dbo].[Enrolment].status = [dbo].[EnrolmentStatus].[_identity])
LEFT JOIN
[dbo].[Student] ON [dbo].[Enrolment].student = [dbo].[Student].[_identity])
LEFT JOIN
[dbo].[Person] ON [dbo].[Student].person = [dbo].[Person].[_identity]
LEFT JOIN
[dbo].[Contact] ON [dbo].[Employer].[_identity] = [dbo].[Contact].employer
WHERE
(([dbo].[EnrolmentStatus].name) = 'training'
OR
([dbo].[EnrolmentStatus].name) = 'enrolled')
This is working fine but what I would like to do is join to the [dbo].[Person] table again but this time joining from another table so the code I effectively need to patch into the above statement is
LEFT JOIN
[dbo].[Trainer] ON [dbo].[Enrolment].Trainer = [dbo].[Trainer].[_identity])
LEFT JOIN
[dbo].[Person] ON [dbo].[Trainer].person = [dbo].[Person].[_identity]
I then need to be able to get from the person table the name of the student and the name of the trainer, so I need 2 records from the person table for every record from the Enrolment table, the fields I need from the person table are the same for both trainer and student in that I am trying to get the given name and surname for both.
Any help or pointers would be most appreciated.
You have to just use replace your from clause with this. You have to just first use the Trainer table join, then Person table, then use the AND keyword to use multiple mapping with single table
FROM (((([dbo].[Enrolment]
LEFT JOIN [dbo].[Course] ON [dbo].[Enrolment].course = [dbo].[Course].[_identity])
LEFT JOIN [dbo].[Employer] ON [dbo].[Enrolment].employer = [dbo].[Employer].[_identity])
LEFT JOIN [dbo].[EnrolmentStatus] ON [dbo].[Enrolment].status = [dbo].[EnrolmentStatus].[_identity])
LEFT JOIN [dbo].[Student] ON [dbo].[Enrolment].student = [dbo].[Student].[_identity])
LEFT JOIN [dbo].[Trainer] ON [dbo].[Enrolment].Trainer = [dbo].[Trainer].[_identity])
LEFT JOIN [dbo].[Person] ON [dbo].[Student].person = [dbo].[Person].[_identity]
AND [dbo].[Trainer].person = [dbo].[Person].[_identity]
LEFT JOIN [dbo].[Contact] ON [dbo].[Employer].[_identity] = [dbo].[Contact].employer
Use aliasing like this..
LEFT JOIN [dbo].[Trainer] ON [dbo].[Enrolment].Trainer = [dbo].[Trainer].[_identity])
LEFT JOIN [dbo].[Person] AS p ON [dbo].[Trainer].person = p.[_identity]
If I get your question right - what you are trying to do is to join the same table twice in your SQL. You have one table Person which has both student and trainer information and you want to see their details side by side in your result set. So you need to join Person once with Student and another time with Trainer
To do this - you will have to join Person table together. Give your tables an alias like the other answers have suggested. Then your FROM clause can look like this -
FROM (((([dbo].[Enrolment]
LEFT JOIN [dbo].[Course] ON [dbo].[Enrolment].course = [dbo].[Course].[_identity])
LEFT JOIN [dbo].[Employer] ON [dbo].[Enrolment].employer = [dbo].[Employer].[_identity])
LEFT JOIN [dbo].[EnrolmentStatus] ON [dbo].[Enrolment].status = [dbo].[EnrolmentStatus].[_identity])
LEFT JOIN [dbo].[Student] ON [dbo].[Enrolment].student = [dbo].[Student].[_identity])
LEFT JOIN [dbo].[Person] P1 ON [dbo].[Student].person = P1.[_identity]
LEFT JOIN [dbo].[Contact] ON [dbo].[Employer].[_identity] = [dbo].[Contact].employer
LEFT JOIN [dbo].[Trainer] ON [dbo].[Enrolment].Trainer = [dbo].[Trainer].[_identity])
LEFT JOIN [dbo].[Person] P2 ON [dbo].[Trainer].person = P2.[_identity]
....
....
Here P1 and P2 are two aliases for [Person]
Hello in my system i have a search page for a student that the admin will be able to view
the students history i have a problem with showing the last name of his/her adviser which is lname_A. This is the code i currently us so far everything is ok except i cant manage to get the lname_a.
$qry_display = "SELECT
a.student_id, a.section_id, a.level, a.photo, a.address, a.father_occupation, a.father_phone, a.father_company, a.mother_occupation, a.mother_phone, a.mother_company,a.gpa,
b.fname, b.sex, b.lname, b.mname, b.birth_date, b.birth_place, b.address, b.father, b.father_degree, b.mother, b.mother_degree,
c.section_name, d.adviser_id , d.lname_a
FROM tbl_er AS a
LEFT OUTER JOIN tbl_enroll AS b ON a.student_id = b.student_id
LEFT OUTER JOIN tbl_section AS c ON a.section_id = c.section_id
LEFT OUTER JOIN tbl_adviser AS d ON a.section_id = d.adviser_id
WHERE a.student_id=".$id." AND a.level='Grade 2'";
Would gladly appreciate any help.
Are you sure you are joining both tables or correct columns?
a.section_id = d.adviser_id
If every student has adviser then you should use inner join rather than left outer join.
When you use left outer join there is chance lname_a is empty when the student doesn't has adviser.
I have a Table which contains student information(name, id, course,....), and I have another table which contains information like(id, student leave)
I need to generate a report, which is by course all the students who were absent....
Am confused on how to do this properly - Do i use an outer join or what cause SQL 5.0 keeps giving me errors like syntax error....
Have to use this query in servlets...!!!
Currently am using the query in 2 parts.... but which is not generating the table properly....
SELECT * FROM Student s LEFT JOIN Attendance a ON a.student_id = s.id WHERE s.course_id = "ENG"
SELECT *
FROM Student s, Attendance a
WHERE s.id = a.student_id
AND s.course_id = "ENG"
AND s.id = <the_retrieved_id>
Should also be possible.
I suggest turning Student.id to Student.student_id to make it clear,
and also use integer for keys in course table.
then use join like Pradeep Singh only with "using":
select * from Student s left join Attendance a using (student_id) where s.course_id="ENG"
Select * From Student s left join Attendance a on a.student_id = s.id where course_id='ENG'