understanding ifNULL function in sql statement

Author: techysanoj

ifNULL function.sql

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+use temp_db;
+
+show tables;
+
+create table emp_3(id int, salary int);
+
+insert into emp_3 values(1, 10000);
+insert into emp_3 values(2, 14253);
+insert into emp_3 values(NULL, 1000);
+insert into emp_3 values(4, NULL);
+
+select * from emp_3;
+
+-- if we add the value in the NULL
+
+select (salary + 20000) from emp_3; -- here null + 20000 is NULL
+
+select (ifNULL(salary, 0) + 10) from emp_3; -- now it will show 10 where ever is NULL value