如何从一个表中插入另一个表中有记录的记录插入表中？

Question

I have table parent and table kids , a parent can have some kids in the kids table (0 or more).

I want to insert to new table parentWithKids only the parents that have kids in the kids table.

So I tried something like:

INSERT INTO parentWithKids
SELECT *
FROM parent p
INNER JOIN kids k ON p.id = k.parent_id

but its not running...what is the issue here?

Answer 1

I assume following schema.

parent:

CREATE TABLE IF NOT EXISTS `parent` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=1;

kids

CREATE TABLE IF NOT EXISTS `kids` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `parent_id` int(11) NOT NULL,
  `name` varchar(255) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=1;

parentwithkids

CREATE TABLE IF NOT EXISTS `parentwithkids` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `parent_id` int(11) NOT NULL,
  `kids` int(11) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=1;

Here is the final query to retrieve the list of parents with number of kids.

INSERT INTO parentWithKids(parent_id, kids)
SELECT DISTINCT p.id, count(k.id)
FROM parent p
INNER JOIN kids k ON p.id = k.parent_id
GROUP BY k.parent_id