Beginning Learning SQL – Post 8 – Less than, Greater than

In SQL, there are also these four operators

  • Less than
  • Greater than
  • Less than or equal to
  • Greater than or equal to

If you remember math as a kid (well probably a teenager), it’s the same concept as you see in math. Let’s say we want to find the students who scored at or above 90% in our sample database:

SELECT StudentID
FROM Stats.Scores
WHERE Score >= '90'

You could also pick out the students who didn’t do so well by running something like this:

SELECT *
FROM Stats.Scores
WHERE Score < '60'

This can only be used in certain data field types (mainly numbers) – but you can also do it against words as well (provided the words are somewhat similar). For example:

SELECT StudentID
FROM Stats.Scores
WHERE StudentID > Student C

Gives us a result of:

1
2
3
4
5
6
7
8
9
10
11
12
13
Student E
Student D
Student H
Student I
Student F
Student G
Student E
Student D
Student H
Student I
Student F
Student G
Student J

It’s also handy against dates and identity fields. These particular operators are somewhat basic but it’s good to have a good understanding of them. So play around with them a little bit and get comfortable with them.