Filtering Rows

 

Next, let’s look at how we can filter rows when selecting data.

 

LIMIT

 

To do that, we can use the LIMIT keyword. This limits the number of rows retrieved by the SELECT statement. For instance, if we write

 

SELECT em_name AS 'Employee Name', gender AS Gender FROM employees LIMIT 3;

 

we’ll get

 

 

Only the first three rows are displayed.

 

DISTINCT

 

Another way to filter rows is to remove duplicates. This can be achieved using the DISTINCT keyword.

 

If we write

 

SELECT gender FROM employees;

 

we’ll get

 

M
M

F

F

M

F

M

F

M

 

as the output.

 

This means that the first two rows in our table have gender = M while the third and fourth rows have gender = F etc.

 

If we want to remove the duplicates, we can write

 

SELECT DISTINCT(gender) FROM employees;

 

We’ll get

 

M

F

 

as the output...