MySQL updates column to always NULL - mysql

Question

I have two tables which basically one is a master table and the other one is a table for developers. From time to time I would copy review the record from the developer table and move it to the master table:
--SHOW CREATE TABLE DOCUMENT --
CREATE TABLE `document` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`url` varchar(1000) CHARACTER SET utf8 NOT NULL,
`title` varchar(1000) CHARACTER SET utf8 NOT NULL,
`content` longtext CHARACTER SET utf8,
`source_type` varchar(100) CHARACTER SET utf8 DEFAULT NULL,
`date_crawled` datetime DEFAULT NULL,
`mime_type` varchar(100) CHARACTER SET utf8 DEFAULT NULL,
`type` varchar(100) CHARACTER SET utf8 DEFAULT NULL,
`date_posted` datetime DEFAULT NULL,
`tier` int(11) DEFAULT NULL,
`html_content` longtext CHARACTER SET utf8,
`dev` varchar(255) CHARACTER SET utf8 NOT NULL,
`dev_document_id` int(11) NOT NULL,
`promote` int(11) DEFAULT NULL,
`domain` varchar(128) CHARACTER SET utf8 DEFAULT NULL,
PRIMARY KEY (`id`,`url`(500),`dev`,`dev_document_id`),
UNIQUE KEY `url` (`url`)
) ENGINE=InnoDB AUTO_INCREMENT=628871 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci ROW_FORMAT=COMPRESSED
--SHOW CREATE TABLE DOCUMENT_DEVELOPER--
CREATE TABLE `document_developer` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`url` varchar(1000) CHARACTER SET utf8 NOT NULL,
`title` varchar(1000) CHARACTER SET utf8 DEFAULT NULL,
`content` longtext CHARACTER SET utf8,
`jurisdiction` varchar(45) CHARACTER SET utf8 DEFAULT NULL,
`source_type` varchar(100) CHARACTER SET utf8 DEFAULT NULL,
`date_crawled` datetime DEFAULT NULL,
`mime_type` varchar(100) CHARACTER SET utf8 DEFAULT NULL,
`type` varchar(100) CHARACTER SET utf8 DEFAULT NULL,
`html_content` longtext CHARACTER SET utf8,
`date_posted` datetime DEFAULT NULL,
`tier` int(11) DEFAULT NULL,
`promote` int(11) NOT NULL,
`modified` tinyint(1) NOT NULL DEFAULT '0',
`date_modified` datetime DEFAULT NULL,
UNIQUE KEY `url_promote_UNIQUE` (`url`,`promote`),
KEY `id` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=637067 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci ROW_FORMAT=COMPRESSED
/*!50100 PARTITION BY LIST (promote)
(PARTITION part0 VALUES IN (-5) ENGINE = InnoDB,
PARTITION part1 VALUES IN (-4) ENGINE = InnoDB,
PARTITION part2 VALUES IN (-3) ENGINE = InnoDB,
PARTITION part3 VALUES IN (-2) ENGINE = InnoDB,
PARTITION part4 VALUES IN (-1) ENGINE = InnoDB,
PARTITION part5 VALUES IN (0) ENGINE = InnoDB,
PARTITION part6 VALUES IN (1) ENGINE = InnoDB,
PARTITION part7 VALUES IN (2) ENGINE = InnoDB) */
The column of dev_document_id will be the id of record in document_developer once the copy is done.
However, when i try to run update as below:
UPDATE document as d INNER JOIN document_developer AS dd ON d.dev_document_id = dd.id
SET
d.content=dd.content
WHERE dd.modified='1' AND dd.promote='2';
it will always give me erroneous content value such as NULL NULL NULL ... Any help will be greatly appreciated.

Answer 1

Your query should be
UPDATE document as d INNER JOIN document_developer AS da ON
d.dev_document_id = da.id
SET
d.content=da.content
WHERE da.modified='1' AND da.promote='2';