Editing Select (SQL) (section)

== Examples ==
{| class="wikitable" style="float: right; clear:right; margin: 1em" border="1"
!Table "T"
!Query
!Result
|-
|align="center"|
{| cellpadding="2" rules="all" style="border: 1px solid gray; text-align: center;"
! C1 !! C2
|-
| 1  || a
|-
| 2  || b
|}
||{{code|2=sql|1=SELECT * FROM T;}}
|align="center"|
{| cellpadding="2" rules="all" style="border: 1px solid gray; text-align: center;"
! C1 !! C2
|-
| 1  || a
|-
| 2  || b
|}
|-
|align="center"|
{| cellpadding="2" rules="all" style="border: 1px solid gray; text-align: center;"
! C1 !! C2
|-
| 1  || a
|-
| 2  || b
|}
||{{code|2=sql|1=SELECT C1 FROM T;}}
|align="center"|
{| cellpadding="2" rules="all" style="border: 1px solid gray; text-align: center;"
! C1
|-
| 1
|-
| 2
|}
|-
|align="center"|
{| cellpadding="2" rules="all" style="border: 1px solid gray; text-align: center;"
! C1 !! C2
|-
| 1  || a
|-
| 2  || b
|}
||{{code|2=sql|1=SELECT * FROM T WHERE C1 = 1;}}
|align="center"|
{| cellpadding="2" rules="all" style="border: 1px solid gray; text-align: center;"
! C1 !! C2
|-
| 1  || a
|}
|-
|align="center"|
{| cellpadding="2" rules="all" style="border: 1px solid gray; text-align: center;"
! C1 !! C2
|-
| 1  || a
|-
| 2  || b
|}
||{{code|2=sql|1=SELECT * FROM T ORDER BY C1 DESC;}}
|align="center"|
{| cellpadding="2" rules="all" style="border: 1px solid gray; text-align: center;"
! C1 !! C2
|-
| 2  || b
|-
| 1  || a
|}
|-
|align="center"|does not exist
||{{code|2=sql|1=SELECT 1+1, 3*2;}}
|align="center"|
{| cellpadding="2" rules="all" style="border: 1px solid gray; text-align: center;"
! `1+1` !! `3*2`
|-
| 2  || 6
|}
|}
Given a table T, the ''query'' {{code|2=sql|1=SELECT * FROM T}} will result in all the elements of all the rows of the table being shown.

With the same table, the query {{code|2=sql|1=SELECT C1 FROM T}} will result in the elements from the column C1 of all the rows of the table being shown. This is similar to a ''[[Projection (relational algebra)|projection]]'' in [[relational algebra]], except that in the general case, the result may contain duplicate rows.  This is also known as a Vertical Partition in some database terms, restricting query output to view only specified fields or columns.

With the same table, the query {{code|2=sql|1=SELECT * FROM T WHERE C1 = 1}} will result in all the elements of all the rows where the value of column C1 is '1' being shown{{snd}} in [[relational algebra]] terms, a ''[[Selection (relational algebra)|selection]]'' will be performed, because of the WHERE clause.  This is also known as a Horizontal Partition, restricting rows output by a query according to specified conditions.

With more than one table, the result set will be every combination of rows.  So if two tables are T1 and T2, {{code|2=sql|1=SELECT * FROM T1, T2}} will result in every combination of T1 rows with every T2 rows.  E.g., if T1 has 3 rows and T2 has 5 rows, then 15 rows will result.

Although not in standard, most DBMS allows using a select clause without a table by pretending that an imaginary table with one row is used. This is mainly used to perform calculations where a table is not needed.

The SELECT clause specifies a list of properties (columns) by name, or the wildcard character (“*”) to mean “all properties”.