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Title:       Incrementing/De-Incrementing columns
Contributor: Bamse
Last Update: Saturday September 2 21:15 EDT 2000



# Here is a MySQL columns drill for you to follow.
#
mysql -uroot -p

CREATE DATABASE TestDB;
USE TestDB;

CREATE TABLE test_table (
test_id INT NOT NULL auto_increment,
var_test VARCHAR(255) NOT NULL,
int_test SMALLINT NOT NULL,
PRIMARY KEY(test_id),
KEY(var_test),
KEY(var_test)
);

SELECT * FROM test_table;

INSERT into test_table (var_test,int_test) VALUES ('1', '1');
SELECT * FROM test_table;

UPDATE test_table SET var_test = var_test+2 WHERE test_id = '1';
UPDATE test_table SET int_test = int_test+2 WHERE test_id = '1';
SELECT * FROM test_table;

UPDATE test_table SET var_test = var_test-1 WHERE test_id = '1';
UPDATE test_table SET int_test = int_test-1 WHERE test_id = '1';
SELECT * FROM test_table;

UPDATE test_table SET int_test=int_test*2, int_test=int_test+1;
SELECT * FROM test_table;

UPDATE test_table SET int_test=var_test*2, int_test=int_test-1;
SELECT * FROM test_table;

DROP DATABASE TestDB;
quit

# Note that "DROP DATABASE TestDB;" does just that. It
# sent the database to binary heaven and it is now deleted.


   Anyone who wishes to make additions or changes to this
MySQL Tip email them to webmaster@linuxguruz.org

   This document is Copyright (c) 1999, 2000 by LinuxGuruz

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