#1

SELECT NULLIF(1,1);

#2

SELECT NULLIF(1,2);

#3

SELECT NULLIF('MySQL NULLIF','MySQL NULLIF');

#4

SELECT NULLIF('MySQL NULLIF','MySQL IFNULL');

#5

SELECT NULLIF(1,NULL);

#6

SELECT NULLIF(NULL,1);

#7

SELECT 1/0; -- cause error

#8

SELECT 1/NULLIF(0,0); -- return NULL

#9

SELECT 
    orderNumber, orderdate, requiredDate, shippedDate, status
FROM
    orders
WHERE
    orderDate BETWEEN '2003-06-01' AND '2003-06-30';

#10

SELECT SUM(IF(status = 'Shipped',1,0)) / 
       SUM(IF(status = 'Cancelled',1,0))
FROM orders
WHERE orderDate BETWEEN '2003-06-01' and '2003-06-30';

#11

SELECT 
    SUM(IF(status = 'Shipped', 1, 0)) / 
    NULLIF(SUM(IF(status = 'Cancelled', 1, 0)), 0)
FROM
    orders
WHERE
    orderDate BETWEEN '2003-06-01' AND '2003-06-30';