Identify if at least one row with given condition exists

Question

Employee table has ID and NAME columns. Names can be repeated. I want to find out if there is at least one row with name like \'kaushik%\'.

So query should return true/f

Answer 1

since you require that the sql query should return 1 or 0, then you can try the following query :-

select count(1) from dual 
where exists(SELECT 1 
             FROM employee
             WHERE name like 'kaushik%')

Since the above query uses Exists, then it will scan the employee table and as soon as it encounters the first record where name matches "kaushik", it will return 1 (without scanning the rest of the table). If none of the records match, then it will return 0.