MySQL- group by and foreign key

Which clause is used with an "aggregate" function?

• GROUP BY

• SELECT

• WHERE

• Both GROUP BY and WHERE

What is the meaning of "GROUP BY" clause?

• Group data by column values

• Group data by row values

• Group data by column and row values

• None of the mentioned

How to select number of employees - department wise from Emp table (EmpNo, DeptNo, EmpName)?

• Select empno, count(*) from Emp Group By deptno;

• Select deptno, count(*) from Emp Group By deptno;

• Select empno, count(*) from Emp Order By deptno;

• Select deptno, count(*) from Emp Order By deptno;

Null values in GROUP BY fields are omitted.

• True

• False

Which statements are true about Group By?

• Group By is used to group set of values based on one or more values

• Group By is used when we use aggregate functions

• Group by does not guarantee sorting the data in any order

• All of above

How to select Maximum Salary of Employee from each Department in Emp table(empno, ename, deptno, sal)?

• Select deptno, sal from Emp Group By deptno Order By Max(Sal);

• Select deptno, sal from Emp Group By deptno having sal = max(sal);

• Select deptno, max(sal) from Emp Group By deptno;

• Select deptno, max(sal) from Emp Order By Max(Sal);

Which of the following is correct to count the total salary dept wise where there are more than two employees in a dept from emp table (empno, ename, deptno, sal)

• SELECT deptno, sum(sal) As totalsal FROM emp GROUP BY deptno HAVING COUNT(empno) = 2

• SELECT deptno, sum(sal) As totalsal FROM emp where COUNT(empno) = 2 GROUP BY deptno

• SELECT deptno, sum(sal) As totalsal FROM emp GROUP BY deptno HAVING COUNT(empno) > 2

• SELECT deptno, sum(sal) As totalsal FROM emp where COUNT(empno) > 2 GROUP BY deptno

Where filters data before grouping and Having filters data after grouping

• True

• False

Which clause is used to remove a foreign key constraint?

• REMOVE

• DELETE

• DROP

• EXCLUDE

Which keyword is used to specify the foreign key after the table is created?

• UPDATE

• ALTER TABLE

• MODIFY

• CHANGE