Difference between revisions of "SELECT Reference"

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SELECT statements may nested - that is the output from one SELECT may be the input to another SELECT.
 
SELECT statements may nested - that is the output from one SELECT may be the input to another SELECT.
  
The output from a SELECT may be added to another table using [[INSERT..SELECT]]
+
The output from a SELECT may be added to another table using [[INSERT .. SELECT]]

Revision as of 11:12, 11 August 2012

The SELECT command is used to show data from a database.

The output from a SELECT statement is always a grid - with a number of rows and a number of columns.

Simple SELECT

The simplest SELECT commands involve a single table:

SELECT name, population
  FROM bbc
 WHERE region='North America'
namepopulation
Canada32000000
Mexico106400000
United States of America295000000
  • The SELECT line determines which columns to show - in this case name and population, both of which are columns of the bbc ta le.
  • The WHERE clause determines which rows to show

The SELECT statement may involve data from more than one table using a JOIN or a UNION.

SELECT statements may nested - that is the output from one SELECT may be the input to another SELECT.

The output from a SELECT may be added to another table using INSERT .. SELECT

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