Difference between revisions of "SELECT Reference"

Revision as of 05:41, 12 December 2012

CREATE TABLE test_image

(
ID NUMBER,
image_filename VARCHAR2(50),
image BLOB
);

@@ Line 1: / Line 1: @@
-{{SELECT Ref}}
+CREATE TABLE test_image
-The [[SELECT]] command is used to show data from a database.
+ (
+ ID NUMBER,
-The output from a SELECT statement is always a grid - with a number of rows and a number of columns.
+  image_filename VARCHAR2(50),
-==Simple SELECT==
+ image BLOB
-The simplest SELECT commands involve a single table:
+ );
-<table>
-<tr><th>SQL</th><th>Result</th></tr>
-<tr><td>
-<source lang='sql'>
-SELECT name, population
-  FROM bbc
-  WHERE region='North America'
-</source>
-</td><td>
-<table class="sqlmine"><tr><th>name</th><th>population</th></tr><tr><td>Canada</td><td class="r">32000000</td></tr><tr><td>Mexico</td><td class="r">106400000</td></tr><tr><td>United States of America</td><td class="r">295000000</td></tr></table>
-</td></tr></table>
-*The SELECT line determines which columns to show - in this case <code>name</code> and <code>population</code>, both of which are columns of the bbc table.
-*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]]