从多个表中选择查询

Question

I have 6 tables and need to retrieve some data at once from those tables. can any body tell me, can I select my values from one query.

These values I needed.

institute_id
institute_name
city_name
options (relate to institute_id) 
mediums (relate to institute_Id)

These are from my tables

CREATE TABLE institutes (
    institute_id INT(4) UNSIGNED NOT NULL AUTO_INCREMENT,
    login_id INT(4) UNSIGNED NOT NULL,
    address_id INT(4) NOT NULL,
    contact_id INT(4) NOT NULL,
    institute_code INT(4) NOT NULL, 
    institute_name VARCHAR(80) NOT NULL, 
    institute_details VARCHAR(80) NOT NULL, 
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

CREATE TABLE address (
    address_id INT(4) UNSIGNED NOT NULL AUTO_INCREMENT,
    address_one VARCHAR(40) NOT NULL, 
    address_two VARCHAR(40) DEFAULT NULL, 
    city_id INT(4) UNSIGNED NOT NULL,
    PRIMARY KEY (address_id),
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

CREATE TABLE city(
    city_id INT(4) UNSIGNED NOT NULL AUTO_INCREMENT,
    city_name VARCHAR(30) NOT NULL, 
    state_id INT(2) UNSIGNED NOT NULL,
    PRIMARY KEY (city_id),
) ENGINE=MyISAM;

CREATE TABLE medium(
    medium_id INT(2) UNSIGNED NOT NULL AUTO_INCREMENT,
    medium_name VARCHAR(30) NOT NULL, 
    PRIMARY KEY (medium_id),
) ENGINE=MyISAM;


CREATE TABLE options(
    option_id INT(2) UNSIGNED NOT NULL AUTO_INCREMENT,
    option_name VARCHAR(60) NOT NULL, 
    PRIMARY KEY (option_id),
) ENGINE=MyISAM;


CREATE TABLE institute_medium(
    im_id INT(4) UNSIGNED NOT NULL AUTO_INCREMENT,
    medium_id INT(2) UNSIGNED NOT NULL,
    institute_id INT(4) UNSIGNED NOT NULL,
    PRIMARY KEY (im_id)
) ENGINE=MyISAM;

those are my tables

I tried like this but Im confuse when Im try to get options and mediums.. there are always more than one option and medium in instutite_medium to one institute...

$query = "SELECT 
              institute_id, institute_name, city_name, 
              DATE_FORMAT(registration_date, '%M %e, %Y') AS date
          FROM 
              institutes 
          INNER JOIN 
              address ON institutes.address_id = address.address_id
          INNER JOIN 
              city ON address.city_id = city.city_id
          ORDER BY 
              registration_date DESC";

any comments are greatly appreciated.

thank you...

Answer 1

You could do the followng:

SELECT 
          institute_id, institute_name, city_name, 
          DATE_FORMAT(registration_date, '%M %e, %Y') AS date,
          GROUP_CONCAT(mediums.name SEPARATOR ', ')
      FROM 
          institutes 
      INNER JOIN 
          address ON institutes.address_id = address.address_id
      INNER JOIN 
          city ON address.city_id = city.city_id
      LEFT JOIN 
          institute_medium ON institutes.institute_id = institute_medium.institute_id
      LEFT JOIN 
          medium ON institute_medium.medium_id = medium.medium_id
      ORDER BY 
          registration_date DESC

Will GROUP_CONCAT(mediums.name SEPARATOR ', ') will basically implode all the medium names.

You could drop the group concat and use mediums.names and use right joins then you'll have the same row multiple times the only variation being the medium name