MySql replace NULL values with empty string
Date Posted: 05-04-2018
In this we will explain MySql replace NULL values with empty string.
Step1: You can create two different tables. using the following query.
CREATE TABLE `users` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`username` varchar(16) NOT NULL,
`name` varchar(40) DEFAULT NULL,
`last_name` varchar(60) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
INSERT INTO `users`(username,name,last_name) VALUES ('xxx','xyz','abc');
CREATE TABLE `billings` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`user_id` int(11) NOT NULL,
`address` varchar(16) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8
INSERT INTO `billings`(user_id,address) VALUES ('1','');
CREATE TABLE `users` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`username` varchar(16) NOT NULL,
`name` varchar(40) DEFAULT NULL,
`last_name` varchar(60) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
INSERT INTO `users`(username,name,last_name) VALUES ('xxx','xyz','abc');
CREATE TABLE `billings` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`user_id` int(11) NOT NULL,
`address` varchar(16) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8
INSERT INTO `billings`(user_id,address) VALUES ('1','');
CREATE TABLE `users` ( `id` int(11) unsigned NOT NULL AUTO_INCREMENT, `username` varchar(16) NOT NULL, `name` varchar(40) DEFAULT NULL, `last_name` varchar(60) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8; INSERT INTO `users`(username,name,last_name) VALUES ('xxx','xyz','abc'); CREATE TABLE `billings` ( `id` int(11) unsigned NOT NULL AUTO_INCREMENT, `user_id` int(11) NOT NULL, `address` varchar(16) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 INSERT INTO `billings`(user_id,address) VALUES ('1','');
Step2: We can use mysql IFNULL function to replace the null values with empty string.
Synatx:
IFNULL(null,"") as value
IFNULL(null,"") as value
IFNULL(null,"") as value
Example:
SELECT u.*,IFNULL(b.address,"") AS address FROM `users` as u LEFT JOIN billings as b on b.user_id=u.id order by u.id
SELECT u.*,IFNULL(b.address,"") AS address FROM `users` as u LEFT JOIN billings as b on b.user_id=u.id order by u.id
SELECT u.*,IFNULL(b.address,"") AS address FROM `users` as u LEFT JOIN billings as b on b.user_id=u.id order by u.id