Optimizing query mysql - mysql
I have 3 tables in which i store some values. Everything is working fine except my query is taking too long to execute. I have around 500.000 rows in table "tickets" at the moment. I would like to know what would be the best way to optimize this query to execute SELECT faster.
One more thing: I would like to know is there a way to update all rows through query (not using my C# app). In this case i need to update column "wonamount" which is in tickets with value that i get by multiplying row "coefficient" with row "uplata" and update column status with value "2".
Here are my tables and sql:
CREATE TABLE IF NOT EXISTS `coefficients` (`number` int(11) DEFAULT NULL,`coefficient` int(11) DEFAULT NULL) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO `coefficients` (`number`, `coefficient`) VALUES
(1, 0),
(2, 0),
(3, 0),
(4, 0),
(5, 0),
(6, 10000),
(7, 7500),
(8, 5000),
(9, 2500),
(10, 1000),
(11, 500),
(12, 300),
(13, 200),
(14, 120),
(15, 80),
(16, 70),
(17, 60),
(18, 50),
(19, 40),
(20, 35),
(21, 30),
(22, 25),
(23, 20),
(24, 15),
(25, 12),
(26, 10),
(27, 9),
(28, 8),
(29, 7),
(30, 6),
(31, 5),
(32, 4),
(33, 3),
(34, 2),
(35, 1);
CREATE TABLE IF NOT EXISTS `draws` (
`iddraws` int(11) NOT NULL AUTO_INCREMENT,
`1` varchar(255) DEFAULT NULL,
`2` varchar(45) DEFAULT NULL,
`3` varchar(45) DEFAULT NULL,
`4` varchar(45) DEFAULT NULL,
`5` varchar(45) DEFAULT NULL,
`6` varchar(45) DEFAULT NULL,
`7` varchar(45) DEFAULT NULL,
`8` varchar(45) DEFAULT NULL,
`9` varchar(45) DEFAULT NULL,
`10` varchar(45) DEFAULT NULL,
`11` varchar(45) DEFAULT NULL,
`12` varchar(45) DEFAULT NULL,
`13` varchar(45) DEFAULT NULL,
`14` varchar(45) DEFAULT NULL,
`15` varchar(45) DEFAULT NULL,
`16` varchar(45) DEFAULT NULL,
`17` varchar(45) DEFAULT NULL,
`18` varchar(45) DEFAULT NULL,
`19` varchar(45) DEFAULT NULL,
`20` varchar(45) DEFAULT NULL,
`21` varchar(45) DEFAULT NULL,
`22` varchar(45) DEFAULT NULL,
`23` varchar(45) DEFAULT NULL,
`24` varchar(45) DEFAULT NULL,
`25` varchar(45) DEFAULT NULL,
`26` varchar(45) DEFAULT NULL,
`27` varchar(45) DEFAULT NULL,
`28` varchar(45) DEFAULT NULL,
`29` varchar(45) DEFAULT NULL,
`30` varchar(45) DEFAULT NULL,
`31` varchar(45) DEFAULT NULL,
`32` varchar(45) DEFAULT NULL,
`33` varchar(45) DEFAULT NULL,
`34` varchar(45) DEFAULT NULL,
`35` varchar(45) DEFAULT NULL,
`datetime` varchar(255) DEFAULT NULL,
PRIMARY KEY (`iddraws`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=162 ;
INSERT INTO `draws` (`iddraws`, `1`, `2`, `3`, `4`, `5`, `6`, `7`, `8`, `9`, `10`, `11`, `12`, `13`, `14`, `15`, `16`, `17`, `18`, `19`, `20`, `21`, `22`, `23`, `24`, `25`, `26`, `27`, `28`, `29`, `30`, `31`, `32`, `33`, `34`, `35`, `datetime`) VALUES
(1, '17', '46', '27', '30', '8', '11', '4', '40', '37', '36', '22', '14', '35', '47', '24', '20', '23', '10', '2', '42', '41', '43', '9', '19', '7', '48', '3', '38', '29', '44', '16', '12', '26', '13', '5', '1391130262'),
(2, '45', '2', '1', '24', '30', '4', '10', '11', '22', '3', '38', '33', '35', '14', '48', '28', '42', '27', '43', '9', '15', '29', '36', '41', '26', '23', '13', '5', '16', '20', '12', '6', '32', '37', '19', '1391134904'),
(3, '12', '46', '32', '15', '14', '41', '45', '6', '9', '20', '26', '2', '47', '37', '33', '39', '34', '17', '16', '23', '35', '29', '44', '36', '18', '40', '22', '4', '27', '30', '38', '21', '3', '43', '24', '1391135221');
CREATE TABLE IF NOT EXISTS `tickets` (
`id_tiketa` int(11) NOT NULL AUTO_INCREMENT,
`idtickets` varchar(45) DEFAULT NULL,
`b1` varchar(45) DEFAULT NULL,
`b2` varchar(45) DEFAULT NULL,
`b3` varchar(45) DEFAULT NULL,
`b4` varchar(45) DEFAULT NULL,
`b5` varchar(45) DEFAULT NULL,
`b6` varchar(45) DEFAULT NULL,
`shop` varchar(45) DEFAULT NULL,
`user` varchar(45) DEFAULT NULL,
`time` varchar(255) DEFAULT NULL,
`status` varchar(45) DEFAULT NULL,
`uplata` varchar(45) DEFAULT NULL,
`draw` varchar(45) DEFAULT NULL,
`qt` varchar(45) DEFAULT NULL,
`wonamount` varchar(45) DEFAULT NULL,
PRIMARY KEY (`id_tiketa`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=138 ;
INSERT INTO `tickets` (`id_tiketa`, `idtickets`, `b1`, `b2`, `b3`, `b4`, `b5`, `b6`, `shop`, `user`, `time`, `status`, `uplata`, `draw`, `qt`, `wonamount`) VALUES
(75, '4-1-170-1367', '41', '47', '17', '24', '15', '44', '170', 'w1', '1391149398', '1', '1', '1', '', ''),
(76, '4-1-170-20104', '23', '27', '13', '7', '14', '42', '170', 'w1', '1391149398', '1', '1', '1', '', ''),
(91, '4-2-170-13887', '16', '4', '13', '35', '30', '9', '170', 'w1', '1391149462', '1', '1', '2', '', ''),
(92, '4-2-170-9701', '2', '32', '7', '15', '5', '34', '170', 'w1', '1391149463', '1', '1', '2', '', ''),
(93, '4-2-170-45661', '23', '24', '22', '27', '48', '6', '170', 'w1', '1391149463', '1', '1', '2', '', ''),
(98, '4-2-170-45503', '36', '13', '33', '10', '29', '9', '170', 'w1', '1391149463', '1', '1', '2', '', ''),
(99, '4-2-170-24095', '19', '35', '11', '36', '46', '40', '170', 'w1', '1391149463', '1', '1', '2', '', ''),
(100, '4-2-170-42832', '27', '32', '17', '29', '7', '21', '170', 'w1', '1391149463', '1', '1', '2', '', ''),
(101, '4-2-170-13570', '22', '23', '32', '6', '1', '28', '170', 'w1', '1391149463', '1', '1', '2', '', ''),
(103, '4-2-170-28122', '15', '10', '11', '9', '14', '48', '170', 'w1', '1391149463', '1', '1', '2', '', ''),
(116, '4-2-170-13095', '28', '20', '33', '42', '26', '14', '170', 'w1', '1391149464', '1', '1', '2', '', ''),
(118, '4-2-170-27646', '23', '14', '37', '27', '24', '19', '170', 'w1', '1391149464', '1', '1', '2', '', ''),
(124, '4-2-170-23302', '20', '23', '15', '38', '4', '45', '170', 'w1', '1391149465', '1', '1', '2', '', '');
SELECT t.idtickets,
t.uplata,
c.coefficient
FROM tickets t
INNER JOIN draws d ON(FIELD(t.b1,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35)>0)
AND (FIELD(t.b2,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35)>0)
AND (FIELD(t.b3,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35)>0)
AND (FIELD(t.b4,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35)>0)
AND (FIELD(t.b5,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35)>0)
AND (FIELD(t.b6,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35)>0)
INNER JOIN coefficients c ON c.number = GREATEST(FIELD(t.b1,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35), FIELD(t.b2,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35), FIELD(t.b3,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35), FIELD(t.b4,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35), FIELD(t.b5,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35), FIELD(t.b6,d.1,d.2,d.3,d.4,d.5,d.6,d.7,d.8,d.9,d.10,d.11,d.12,d.13,d.14,d.15,d.16,d.17,d.18,d.19,d.20,d.21,d.22,d.23,d.24,d.25,d.26,d.27,d.28,d.29,d.30,d.31,d.32,d.33,d.34,d.35))
WHERE t.draw='1'
AND t.status = '1'
AND d.iddraws='1'
And yes, i need to do that for each t.draw and d.iddraws which will be same values.
While my answer is fairly general, I am assuming you are using MySQL.
Short Answer:
Do the following things one by one in the order mentioned while measuring performance improvement with each step.
Add Indexes on tickets.draw and tickets.status. Also add an index (primary key will be even better) on coefficients.number.
Use int instead of varchar wherever possible.
Convert query to stored procedure to save values of FIELD calls and reuse these values in GREATEST instead of calling FIELD again with same values.
Move calls to FIELD at INSERT/UPDATE time instead of SELECT.
Yes, you can update all rows through query. Use your SELECT query and make the following changes to it:
Replace SELECT t.idtickets,t.uplata, c.coefficient FROM by UPDATE
Add SET t.wonamount = c.coefficient*t.uplata, t.status='2' before WHERE ...
(Really) Long Answer:
Your question is a very good case for discussing SQL optimization as there are many optimization techniques that can be applied here. Let me discuss them in increasing order of complexity, so that you can implement them one by one till you are happy with the results. I will also generalize every point for community's benefit while giving precise suggestions to you. Let's start:
All SQL optimization starts with EXPLAIN. It's a sort of black magic that tells what's wrong with your query. Simply add the EXPLAIN keyword before the SELECT keyword in your query and you get a wealth of information on how your query is executed behind the scene. Here is the EXPLAIN output of your query (some fields removed for sake of brevity):
+-------+-------+---------------+---------+-------+------+-----------------+
| table | type | possible_keys | key | ref | rows | Extra |
+-------+-------+---------------+---------+-------+------+-----------------+
| d | const | PRIMARY | PRIMARY | const | 1 | |
| t | ALL | NULL | NULL | NULL | 13 | Using where |
| c | ALL | NULL | NULL | NULL | 35 | Using where;... |
+-------+-------+---------------+---------+-------+------+-----------------+
Each row covers a table involved in your query. Two important fields to look at here are key and rows. rows tells the number of rows of that table scanned for the query. The more this number, the more data MySQL has to scan, and therefore the slower your query. key tells if MySQL is using any shortcut to reduce rows. In the absence of any key, MySQL has to scan all rows of that table. So, we need to supply keys (also called indexes) to MySQL so that it can reduce rows and execute queries fast.
Here, table t (i.e. tickets) is not using any key and therefore scanning all rows (there are 13 rows in the sample data you provided in your fiddle, and 500,000 of them in the real data). So, we add keys (or indexes) to those fields of tickets table that are involved in decision making in this query. These fields are draw and status (... WHERE t.draw='1' AND t.status = '1'...).
mysql> ALTER TABLE tickets ADD INDEX idx_draw(draw);
mysql> ALTER TABLE tickets ADD INDEX idx_status(status);
Similarly, coefficients will benefit by index on number. A PRIMARY KEY on number will be even better if numbers are unique.
Integer data types (short, int, long, etc.) are significantly faster than character data types (char, varchar, etc.). So, avoid using character data types for integer data. In your data, all fields in draws table, and almost all fields in tickets table contain numeric data. (Booleans can be stored as byte instead of varchar. Also consider storing timestamps as int or long instead of varchar.)
FIELD is a costly call, especially if given a lot of arguments, as has to do a lot of work. In your query there are six distinct FIELD calls, and each is repeated in the call to GREATEST function, making 12 calls in total. Consider using stored procedures which allow you to save results of function calls in variables and reuse them later.
Performing validations during INSERT/UPDATE is better than performing them during SELECT. Consider validating your tickets.b1-b6 against draws.1-35 while inserting/updating instead of querying and your SELECT query will be much simpler and faster. The result of GREATEST can also be calculated at insert/update time and saved in an extra field in the tickets table to avoid recalculation every time during SELECT.
As with all queries, your query may need more optimizations when your data grows 100-1000 times its current size, but these should be enough for now.
does your db have indexes?
MYSQL indexes
Related
Absenteeism query showing date as employee is absent
I'm trying to generate an absenteeism query with the date employees were absent.
Table "ci_admin":
DROP TABLE IF EXISTS `ci_admin`;
CREATE TABLE `ci_admin` (
`admin_id` int(11) NOT NULL AUTO_INCREMENT,
`admin_role_id` int(11) NOT NULL,
`department_id` int(11) NOT NULL,
`firstname` varchar(255) NOT NULL,
`lastname` varchar(255) NOT NULL,
`emp_photo` varchar(255) NOT NULL,
PRIMARY KEY (`admin_id`)
);
INSERT INTO `ci_admin` VALUES ('1', '20170079320', '1', '1', 'AHMED', 'MAKOKHA', '125.jpg'), ('2', '20170079321', '1', '1', 'MARIAM', 'AHMED', '2.png'), ('3', '20170080091', '2', '3', 'SALAHUDEEN', 'AHMED', '3.png'), ('4', '20130080083', '2', '2', 'NURU', 'ABBAS', '4.png'), ('5', '20170080092', '5', '1', 'HIRBO', 'ALI', '5.png');
Table "ci_department":
DROP TABLE IF EXISTS `ci_department`;
CREATE TABLE `ci_department` (
`department_id` int(11) NOT NULL AUTO_INCREMENT,
`admin_id` int(11) NOT NULL,
`department_name` varchar(225) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
PRIMARY KEY (`department_id`)
);
INSERT INTO `ci_department` VALUES ('1', 'INFORMATION COMMUNICATION TECHNOLOGY'), ('2', 'HUMAN RESOURCE'), ('3', 'PROCUREMENT');
Table "ci_admnin_roles":
DROP TABLE IF EXISTS `ci_admin_roles`;
CREATE TABLE `ci_admin_roles` (
`admin_role_id` int(11) NOT NULL AUTO_INCREMENT,
`admin_role_title` varchar(30) CHARACTER SET utf8 NOT NULL,
PRIMARY KEY (`admin_role_id`)
);
INSERT INTO `ci_admin_roles` VALUES ('1', 'Super Admin'), ('2', 'ADMIN'), ('3', 'ACCOUNTANT'), ('4', 'OPERATOR'), ('5', 'IT OFFICER'), ('6', 'APPLICANT');
Table "ci_attendance":
DROP TABLE IF EXISTS `ci_attendance`;
CREATE TABLE `ci_attendance` (
`attendance_id` int(11) NOT NULL AUTO_INCREMENT,
`attendance_date` date NOT NULL,
`admin_id` int(11) NOT NULL,
`check_in` time NOT NULL,
`check_out` time NOT NULL,
PRIMARY KEY (`attendance_id`)
);
INSERT INTO `ci_attendance` VALUES ('1', '2022-12-22', '1', '08:15:00', '18:30:00'), ('2', '2022-12-22', '2', '09:00:00', '18:30:00'), ('3', '2022-12-22', '3', '10:00:00', '19:30:00'), ('4', '2020-02-21', '1', '10:30:00', '20:30:00'), ('5', '2023-12-12', '2', '10:00:00', '21:30:00'), ('6', '2023-12-23', '3', '10:00:00', '22:30:00'), ('7', '2023-12-22', '3', '08:00:00', '17:30:00'), ('8', '2021-02-21', '2', '09:00:00', '18:30:00'), ('9', '2024-12-12', '3', '10:00:00', '19:30:00'), ('10', '2024-12-23', '1', '10:00:00', '20:30:00'), ('11', '2024-12-22', '2', '10:00:00', '21:30:00'), ('12', '2022-02-21', '3', '10:00:00', '22:30:00'), ('13', '2022-12-12', '1', '08:00:00', '17:30:00'), ('14', '2022-12-23', '3', '09:00:00', '18:30:00'), ('15', '2022-12-02', '2', '10:00:00', '19:30:00'), ('16', '2020-02-21', '1', '09:45:00', '22:00:00'), ('17', '2023-12-12', '2', '10:00:00', '21:30:00'), ('18', '2020-12-23', '3', '10:00:00', '22:30:00'), ('19', '2023-12-22', '1', '08:00:00', '17:30:00'), ('20', '2021-02-21', '2', '09:00:00', '18:30:00'), ('21', '2024-12-03', '2', '10:00:00', '19:30:00'), ('22', '2021-12-23', '1', '10:00:00', '20:30:00'), ('23', '2024-10-22', '3', '10:00:00', '21:30:00'), ('24', '2022-02-21', '3', '10:00:00', '22:30:00'), ('25', '2022-12-12', '1', '08:00:00', '17:30:00'), ('26', '2022-09-23', '2', '09:00:00', '18:30:00'), ('27', '2022-12-22', '4', '10:00:00', '19:30:00'), ('28', '2020-02-21', '1', '10:00:00', '20:30:00'), ('29', '2023-04-12', '5', '10:00:00', '21:30:00'), ('30', '2023-12-03', '4', '10:00:00', '22:30:00'), ('31', '2023-12-22', '1', '08:00:00', '17:30:00'), ('32', '2021-02-21', '5', '09:00:00', '18:30:00'), ('33', '2024-12-12', '4', '10:00:00', '19:30:00');
My current MySQL query which displays employees who are absent does not include the date when the employee is absent:
SELECT ci_admin.emp_no,
ci_admin.firstname,
ci_admin.lastname,
ci_admin.emp_photo,
ci_department.department_name,
ci_admin_roles.admin_role_title
FROM ci_admin
INNER JOIN ci_department ON ci_department.department_id = ci_admin.department_id
INNER JOIN ci_admin_roles on ci_admin_roles.admin_role_id=ci_admin.admin_role_id
WHERE ci_admin.is_deleted = 0
AND ci_admin.admin_id NOT IN (SELECT ci_attendance.admin_id
FROM ci_attendance
WHERE ci_attendance.attendance_date BETWEEN '2023-01-01' AND '2023-01-31')
ORDER BY ci_admin.department_id
I want the specific date that an employee is absent to be included in my query. How can I modify my query?
How to find start time of last GPS route
I have data from GPS trackers.
Let's say something like:
CREATE TABLE IF NOT EXISTS `tab_gps` (
`id` int(6) unsigned NOT NULL,
`speed` int(3) unsigned NOT NULL,
`time` time NOT NULL,
`tracker_name` varchar(200) NOT NULL,
PRIMARY KEY (`id`)
) DEFAULT CHARSET=utf8;
and some sample data:
('1', '5', '07:00', 'car'),
('2', '10', '07:10', 'car'),
('3', '0', '07:20', 'bus'),
('4', '0', '07:30', 'car'),
('5', '0', '07:40', 'car'),
('6', '0', '07:50', 'car'),
('7', '20', '08:00', 'car'),
('8', '40', '08:10', 'bus'),
('9', '15', '08:15', 'car'),
('10', '0', '08:32', 'car'),
('11', '0', '08:40', 'car'),
('12', '0', '08:52', 'bus'),
('13', '12', '09:10', 'car'),
('14', '0', '09:25', 'car'),
('15', '0', '09:30', 'car'),
('16', '0', '09:35', 'car'),
('17', '10', '09:41', 'car'),
('18', '5', '09:46', 'car');
('19', '0', '09:50', 'car');
The question is how to find the time when specific 'tracker_name' started his route
So in my example algorithm in my head is:
SELECT * FROM tab_gps WHERE tracker_name='car' then
find the last position with speed=0 (which have next positions >0)
and the next position is the TIME which I am looking for
In my example, it is a position time: 09:41 (id = 17)
I am trying to use:
select max(time) from tab_gps where tracker_name='car' and speed <>0
Here is the Fiddle to better understanding: http://sqlfiddle.com/#!9/834371
Well, for the final route, you can do: select g.* from tab_gp2 g where g.tracker_name = 'car' and g.id > (select coalesce(max(g2.id), -1) from tab_gps g2 where g2.speed = 0 and g2.tracker_name = 'car' ); Here is a db<>fiddle illustrating the logic.
Sql order by two tables
I have 2 relations: tables and tablegroups. One table can be in one tablegroup and one tablegroup contains multiple tables. I need a select that returns the following output: All tables from the tablegroup with the sortid 0 -> the tables again sorted by their sortid and so on for all the tables. Is this possible in Sql(Mysql dbms)? Table table_id, name, pax, createdate, lastupdate, tablegroup_id, sort_id, '2', 'tisch 02', '6', NULL, NULL, '1', '3' '3', 'tisch 03', '4', NULL, NULL, '1', '1' '4', 'tisch 04', '2', NULL, NULL, '1', '2' '5', 'tisch 05', '8', NULL, NULL, '1', '4' '6', 'tisch 101', '4', NULL, NULL, '2', '1' '7', 'tisch 102', '6', NULL, NULL, '2', '2' '8', 'stube 01', '2', NULL, NULL, '3', '2' '9', 'stube 02', '3', NULL, NULL, '3', '1' Tablegroups tablegroup_id, name, notiz, color, customer_id, sort_id, visible '1', 'garten', NULL, '1', '1', '2', '1' '2', 'lounge', NULL, '2', '1', '3', '1' '3', 'stube', '', '7', '1', '1', '1' Expected Output: 'stube 01' 'stube 02' 'tisch 03' 'tisch 04' 'tisch 05' 'tisch 101' 'tisch 102'
Inner join table and tablegroups on a common tablegroup_id and ORDER BY the sort_id of tablegroups and then the sort_id of table. SELECT t.name FROM table t INNER JOIN tablegroups tg ON tg.tablegroup_id = t.tablegroup_id ORDER BY tg.sort_id, t.sort_id;
Get last messages from table ordered by created_at
Maybe it's something continuous question, but I need little help. I have a table CREATE TABLE `ticket_message` ( `id` int(11) NOT NULL, `ticket_id` int(11) NOT NULL, `message` text COLLATE utf8_unicode_ci NOT NULL, `created_at` int(11) NOT NULL, `updated_at` int(11) NOT NULL, `user_flag` tinyint(2) NOT NULL ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci; I just need to get last messages, example: Here it is: '57', '26', 'Hello\r\n', '1474019653', '1474019653', '0' '58', '26', 'Where is my order?', '1474019672', '1474019672', '0' '59', '27', 'Hi', '1474019824', '1474019824', '0' '60', '28', 'Hi\r\n', '1474019921', '1474019921', '0' '61', '28', 'Where is my item?', '1474019933', '1474019933', '0' '62', '26', 'Hello', '1474019983', '1474019983', '1' '63', '26', 'Hello', '1474020069', '1474020069', '0' '64', '26', 'fdsfdsfds', '1474020191', '1474020191', '1' '65', '26', 'fdsfdsfdsfdsfdsfdsfs', '1474020256', '1474020256', '0' '66', '26', 'fdsfsfsfdsfs', '1474020358', '1474020358', '0' '67', '27', 'hello', '1474020872', '1474020872', '1' '68', '27', 'how are you', '1474020953', '1474020953', '0' '69', '27', 'okey', '1474020963', '1474020963', '0' '70', '29', 'This is a test message', '1474021973', '1474021973', '0' '71', '29', 'This is also a test message', '1474023004', '1474023004', '1' '72', '30', 'Test message', '1474025254', '1474025254', '0' '73', '30', 'Test Reply Message', '1474025473', '1474025473', '1' '74', '28', '123', '1475166801', '1475166801', '1' '75', '27', 'foo\r\n', '1475167415', '1475167415', '1' I just want a query, maybe "raw", maybe "yii2", that return me Test Reply Message foo fdsfsfsfdsfs This is also a test message 123
SELECT * FROM ticket_message ORDER BY created_at DESC LIMIT 5; If the framework won't let you say that, the fie on them. (GROUP BY is not appropriate.) (Subqueries are not required.)
MySQL: Cross table Referencing (primary, master, name) for categories and subcategories?
I am creating a table labeled categories where main catgory(parent column) contains 0 and where subcategory contains the ID of the parent category. I heard it is called Referencing. My question: Do i have this table strucutred properly? Or is there a better way like implementing a traversal tree or similar method? CREATE TABLE `categories` ( `primary_id` int(11) NOT NULL auto_increment, `master_id` int(11) NOT NULL default '0', `name` varchar(50) NOT NULL default '', PRIMARY KEY (`c_id`) ) INSERT INTO `categories` (`primary_id`, `master_id`, `name`) VALUES (1, '0', 'Games'), (2, '0', 'Technology'), (3, '0', 'Science'), (4, '0', 'Pop Culture'), (5, '0', 'Jobs/Services'), (6, '0', 'Blogs'), (7, '1', 'Computer'), (8, '1', 'Game Console'), (9, '2', 'Cellphone'), (10, '2', 'Audio/Video/Photos'), (11, '2', 'Laptop'), (12, '2', 'Others >'), (13, '3', 'Human Body'), (14, '3', 'Ocean Life'), (15, '3', 'Plant Life'), (16, '3', 'Animal Life'), (17, '4', 'Artist'), (18, '4', 'Upcoming'), (19, '5', 'Jobs'), (20, '5', 'Tutoring'), (21, '5', 'Seminars'), (22, '5', 'Haircuts'), (23, '9', 'Iphone'), (24, '9', 'Android'), (25, '9', 'Windows Mobile'), (26, '11', 'Toshiba'), (27, '11', 'HP'), (28, '11', 'Apple'),
If you use the InnoDB engine, you can enforce referential integrity for your tables. That way, you can make sure you never insert a category which does not have matching parent id, cascade delete child categories when you delete the parent, etc. Change your create statement to: CREATE TABLE `categories` ( `primary_id` int(11) NOT NULL auto_increment, `master_id` int(11) NOT NULL default '0', `name` varchar(50) NOT NULL default '', PRIMARY KEY (`c_id`), KEY `fk_master_id1` (`master_id`), CONSTRAINT `fk_master_id1` FOREIGN KEY (`master_id`) REFERENCES `master` (`id`) ON DELETE RESTRICT ON UPDATE RESTRICT ) ENGINE=InnoDB DEFAULT CHARSET=latin1; While this strategy works sufficiently well for most cases, you might also want to look at other strategies for implementing tree-like structures and the challenges that come with querying them effectively. See this answer on SO for more information on alternative designs for storing tree-like structures in MySQL.