Sometime we just need to compare left and right table to ensure the data are tally. There’s 2 SQL statement we can use to achieve this.
Example 1
SELECT table1.ID FROM table1 WHERE table1.ID NOT IN(SELECT table2.ID FROM table2)
Example 2
SELECT table1.ID FROM table1 LEFT OUTER JOIN table2 ON table1.ID = table2.ID WHERE table2.ID IS NULL