fetching required data using joins in mysql -
my tables :
mysql> select * professor; +-------+--------+--------+--------+------+ | empid | name | status | salary | age | +-------+--------+--------+--------+------+ | 1 | arun | 1 | 2000 | 23 | | 2 | benoy | 0 | 3000 | 25 | | 3 | chacko | 1 | 1000 | 36 | | 4 | divin | 0 | 5000 | 32 | | 5 | edwin | 1 | 2500 | 55 | | 7 | george | 0 | 1500 | 46 | +-------+--------+--------+--------+------+ 6 rows in set (0.00 sec) mysql> select * works; +----------+-------+---------+ | courseid | empid | classid | +----------+-------+---------+ | 1 | 1 | 10 | | 2 | 2 | 9 | | 3 | 3 | 8 | | 4 | 4 | 10 | | 5 | 5 | 9 | | 6 | 1 | 9 | | 2 | 3 | 10 | | 2 | 1 | 7 | | 4 | 2 | 6 | | 2 | 4 | 6 | | 2 | 5 | 2 | | 7 | 5 | 6 | | 3 | 5 | 2 | | 6 | 4 | 10 | +----------+-------+---------+ 14 rows in set (0.00 sec) mysql> select * course; +----------+------------+--------+ | courseid | coursename | points | +----------+------------+--------+ | 1 | maths | 5 | | 2 | science | 1 | | 3 | english | 6 | | 4 | social | 4 | | 5 | malayalam | 20 | | 6 | arts | 25 | | 7 | biology | 20 | +----------+------------+--------+ 7 rows in set (0.00 sec)
question :
return name(s) of professor(s) taught number of courses in class 10
query tried :
select professor.name,works.courseid,works.empid,works.classid professor inner join works on professor.empid=works.empid works.classid=10 group works.courseid
i know imcomplete/incorrect. pls me required result.
select professor.name, count(works.courseid) works inner join professor on professor.empid = works.empid work.classid = 10 group professor.name order count(works.courseid) desc limit 1
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