difference between a main key and a candidate key

MySQL Workbench Will the following select statements work? If the queries don’t work, explain why and then correct them.a-) SELECT NAME, EMPLOYEE_ID, SALARYFROM EMPLOYEE_TBL E, EMPLOYEE_PAY_TBL EPWHERE EMPLOYEE_ID = EMPLOYEE_ID AND NAME LIKE '%MITH';b-) SELECT E.NAME, E.EMPLOYEE_ID, EP.SALARYFROM EMPLOYEE_TBL E, EMPLOYEE_PAY_TBL EPWHERE NAME LIKE '%MITH';c-) SELECT E.NAME, E.EMPLOYEE_ID, EP.SALARYFROM EMPLOYEE_TBL E, EMPLOYEE_PAY_TBL EPWHERE E.EMPLOYEE_ID = EP.EMPLOYEE_ID AND E.NAME LIKE '%MITH';d-) SELECT ENAME, COUNT(*)FROM EMPWHERE ENAME = '&NAME'ORDER BY ENAME;e-) SELECT DEPT_ID, COUNT(*)FROM EMPGROUP BY DEPT_IDHAVING ENAME='ALIYE';f-) SELECT F_NAME, L_NAMEWHERE F_NAME LIKE '%A'FROM EMP, DEPT;g-) SELECT NAME, SALARYFROM DEPT, EMPWHERE DEPT.ID = EMP.ID AND SUM(SALARY);

Under what circumstances is it appropriate to say that two select statements from the same table both satisfy the union's requirements?

What’s the difference between the UNION and UNION ALL set operators?

The InstantRide Driver Relationship team wants to learn how many travels each driver has done in the month of October. You need to send them the DRIVER_ID, and two calculated columns: DAY and RIDES. The DAY column is calculated using the DAY() function with the TRAVEL_START_TIME as the argument. The RIDES column is calculated by using the COUNT() function to determine the number of rides given for each day. Filter the results with the MONTH function.

Ask the user to enter the name of a fruit. Your program should search the provided ”fruits-database.txt” for the fruit. If the fruit is available, print the price per pound of the fruit. If it's not in the database, print “The fruit does not exist”.

22. The primary key is selected from the: a. composite keys b. determinants c. candidate keys d. foreign keys