Should i use LEFT JOIN OR INNER JOIN or RIGHT JOIN for joining 3 different query into a single query

manpreet Best Answer 3 years ago

FIRST QUERY

$sql="SELECT distinct(syllabus.syllabusName) as subjectName,$cid as courseId, stud.batchId as batchId,course.courseId,course.syllabusId AS subjectID,course.unitId,stud.studentID as studentID  ,concat(stud.studentFirstName,' ',stud.studentLastName,' ',stud.studentRegistrationNumber) AS studentName
            FROM studentdetails  stud           
            INNER JOIN  `coursemapping` course 
            ON  stud.`courseId`=course.courseId
            INNER JOIN syllabus syllabus
            ON  course.syllabusId=syllabus.syllabusId 
            WHERE course.courseId ='$cid' AND course.syllabusId='$sid' AND stud.`batchId`='$bid'";  

SECOND QUERY

     $sql=" SELECT A.assignmentId, A.unitId, B.assignmentName, C.com/tag/assignments">assignmentsBatchId AS batchId, C.courseId AS courseId,C.assignmentMappingId, D.studentId, concat( E.studentFirstName, ' ', E.studentLastName, ' ', E.studentRegistrationNumber ) AS studentName
            FROM studentdetails E
            INNER JOIN com/tag/assignments">assignmentscompleted D ON E.studentId = D.studentId
            INNER JOIN com/tag/assignments">assignmentsbatch C ON D.assignmentId = C.assignmentMappingId
            INNER JOIN com/tag/assignments">assignments B ON D.assignmentId = B.assignmentId
            INNER JOIN com/tag/assignments">assignmentsMapping A ON B.assignmentId = A.assignmentId
            WHERE A.assignmentId = '$sid'
            AND C.com/tag/assignments">assignmentsBatchId = '$bid'
            AND C.courseId ='$cid'";

THIRD QUERY

    $sql    =   "SELECT distinct(C.syllabusName) as subjectName,B.maxAccadamicMarks as com/tag/marks">marksScored,B.academicMarks as maxMarks,B.com/tag/marks">marksPercentage as percentage  
                    FROM studentdetails A INNER JOIN com/tag/marks">marks B 
                    ON A.studentId=B.studentId AND A.courseId=B.courseId AND A.batchId=B.batchId 
                    INNER JOIN syllabus C 
                    ON  B.syllabusId=C.syllabusId WHERE A.studentUserName='$studentUserName'";

Here i need to com/tag/join">join all the three query in order to fetch the subject,student,acccom/tag/marks">marks,com/tag/marks">marks,percentage? how to com/tag/join">join all this three query to single query