The SELECT statement for SQL

Select statements are used to select data from a table.

The result is stored in a result table, called a result set.

SQL SELECT Syntax

SELECT column name from table name

And:

SELECT * FROM table name

Note : The SQL statement is not case sensitive. Select is equivalent to select.

SQL SELECT Instance

To get the contents of a column named "LastName" and "FirstName" (from a database table named "Persons"), use a SELECT statement like this:

SELECT Lastname,firstname from Persons

"Persons" table: City

Id	LastName	FirstName	Address
1	Adams	John	Oxford Street	London
2	Bush	George	Fifth Avenue	New York
3	Carter	Thomas	Changan Street	Beijing

Results:

LastName	FirstName
Adams	John
Bush	George
Carter	Thomas

SQL SELECT * Instance

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

Use the symbol * instead of the name of the column, just like this:

*From Persons

Tip: An asterisk (*) is a shortcut to select all columns.

Results:

City

Id	LastName	FirstName	Address
1	Adams	John	Oxford Street	London
2	Bush	George	Fifth Avenue	New York
3	Carter	Thomas	Changan Street	Beijing

SQL SELECT DISTINCT Statement

In the table, duplicate values may be included. That's not a problem, but sometimes you might want to just list different values (distinct).

Keyword DISTINCT is used to return only different values.

Grammar:

SELECT DISTINCT column name from table name

Using DISTINCT Keywords

If you want to pick all the values from the company column, we need to use the SELECT statement:

SELECT Company from Orders

"Orders" table:

Company

	OrderNumber
Ibm	3532
W3school	2356
Apple	4698
W3school	6953

Results:

Company
Ibm
W3school
Apple
W3school

Note that in the result set, W3school is listed two times.

To select only a different value from the company column, we need to use the Select DISTINCT statement:

DISTINCT

Results:

Company
Ibm
W3school
Apple

Now, in the result set, "W3school" is listed only once.

The SELECT statement for SQL