Friday, 7 July 2017

SQL SELECT

SQL SELECT Statement



This chapter will explain the SELECT and the SELECT * statements.


The SQL SELECT Statement

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
NoteNote: 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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