course content

Course Content

Introduction to SQL

Retrieving Distinct RowsRetrieving Distinct Rows

Note that the SELECT statement returns all rows in a given column. However, what if we don't need all the values ​​from a column, especially when they are duplicated, and we only need unique values? For such cases, it is convenient to use the keyword DISTINCT, placed immediately before the column names. Let's take a look at an example:

Task

You have to retrieve distinct (unique) continent values.

Here's a short example of the country table:

idnamecontinentregionsurfaceareacapitalpopulation
1JapanAsiaEastern Asia377829Tokyo126714000
2LatviaEuropeNULL64589Riga2424200
3MexicoNorth AmericaCentral America1958201Mexico City98881000
.....................
15MaltaEuropeSouthern Europe316Valletta380200

Everything was clear?

Section 1. Chapter 4
toggle bottom row