Structured Query Language tutorial

Structured Query Language tutorial (select command ):


This  will explain the SELECT and the SELECT * statements.
The SELECT statement is used to select data from a database.
The result is stored in a result table, called the result-set.

SQL SELECT Syntax

SELECT column_name(s)
FROM table_name

and

SELECT * FROM table_name

Note: SQL is not case sensitive. SELECT is the same as select.

An SQL SELECT Example

The "Persons" table:

P_Id LastName FirstName Address City
1 Hansen Ola Timoteivn 10 Sandnes
2 Svendson Tove        Borgvn 23 Sandnes
3 Pettersen Kari Storgt 20 Stavanger


Now we want to select the content of the columns named "LastName" and "FirstName" from the table above.

We use the following SELECT statement:

SELECT LastName,FirstName FROM Persons

The result-set will look like this:

LastName FirstName
Hansen     Ola
Svendson Tove
Pettersen Kari

SELECT * Example

Now we want to select all the columns from the "Persons" table.

We use the following SELECT statement: 

SELECT * FROM Persons

Tip: The asterisk (*) is a quick way of selecting all columns!

The result-set will look like this:

P_Id LastName FirstName Address City
1 Hansen Ola Timoteivn 10 Sandnes
2 Svendson Tove Borgvn 23 Sandnes
3 pettersen Kari Storgt 20 Stavanger

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