MySQL SELECT
The MySQL SELECT Statement
To choose data from a database, use the SELECT statement.
The information that is returned is kept in a result table known as the result-set.
SELECT Syntax
SELECT column1, column2, ...
FROM table_name;
The table you wish to pick data from has field names like column1, column2,… in this case. Use the following syntax to select every field in the table that is available:
SELECT * FROM table_name;
Demo Database
We’ll be using the well-known Northwind sample database in this tutorial.
A sample from the “Customers” table in the Northwind sample database is shown below:
| CustomerID | CustomerName | ContactName | Address | City | PostalCode | Country |
|---|---|---|---|---|---|---|
| 1 | Alfreds Futterkiste | Maria Anders | Obere Str. 57 | Berlin | 12209 | Germany |
| 2 | Ana Trujillo Emparedados y helados | Ana Trujillo | Avda. de la Constitución 2222 | México D.F. | 05021 | Mexico |
| 3 | Antonio Moreno Taquería | Antonio Moreno | Mataderos 2312 | México D.F. | 05023 | Mexico |
| 4 | Around the Horn | Thomas Hardy | 120 Hanover Sq. | London | WA1 1DP | UK |
| 5 | Berglunds snabbköp | Christina Berglund | Berguvsvägen 8 | Luleå | S-958 22 | Sweden |
SELECT Columns Example
The following SQL statement selects the “CustomerName”, “City”, and “Country” columns from the “Customers” table:
Example
SELECT CustomerName, City, Country FROM Customers;
SELECT * Example
The following SQL statement selects ALL the columns from the “Customers” table:
Example
SELECT * FROM Customers;
The MySQL SELECT DISTINCT Statement
To retrieve just distinct (different) data, use the SELECT DISTINCT command.
A column in a database may have a lot of duplicate entries, and there may be instances when you just want to list the unique values.
SELECT DISTINCT Syntax
SELECT DISTINCT column1, column2, …
FROM table_name;
SELECT Example Without DISTINCT
The “Country” column in the “Customers” table has all values (including duplicates) selected by the SQL query that follows:
Example
SELECT Country FROM Customers;
Now, let us use the SELECT DISTINCT statement and see the result.
SELECT DISTINCT Examples
The following SQL statement selects only the DISTINCT values from the “Country” column in the “Customers” table:
Example
SELECT DISTINCT Country FROM Customers;
The number of distinct (different) nations in the “Customers” table is counted and returned using the SQL statement that follows:
Example
SELECT COUNT(DISTINCT Country) FROM Customers;
