I have two tables in mysql.i want to check a field in first table.If field is not empty then search in same table else search in other table.
For Example
CREATE TABLE IF NOT EXISTS `crm_list` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(22) NOT NULL,
`status` int(22) NOT NULL DEFAULT '1',
`dateupdated` date NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=9 ;
CREATE TABLE IF NOT EXISTS `test` (
`id` int(22) NOT NULL AUTO_INCREMENT,
`rec` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`myname` varchar(22) NOT NULL,
`list_id` int(22) NOT NULL
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ;
In first table i want to check if name is not empty/null then
WHERE crm_list.status=1 AND crm_list.dateupdated=2012-04-13
otherwise check in second table like
WHERE test.myname='abc'
Relationship is list_id in second table which is the id of first table
Here is one approach. The conditions are just expressed in the where clause:
select cl.*
from crm_list cl
where (cl.status=1 AND cl.dateupdated=2012-04-13 and coalesce(cl.name, '') <> '') or
(coalesce(cl.name, '') = '' and
cl.list_id in (select list_id from test where myname - 'abc'
)
Related
I have a table that contains all translations of words:
CREATE TABLE `localtexts` (
`Id` int(11) NOT NULL,
`Lang` char(2) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT 'pe',
`Text` varchar(300) DEFAULT NULL,
`ShortText` varchar(100) NOT NULL,
`DbVersion` timestamp NOT NULL DEFAULT current_timestamp(),
`Status` int(11) NOT NULL DEFAULT 1
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
As example there is a table that refers to localtexts:
CREATE TABLE `composes` (
`Status` int(11) NOT NULL DEFAULT 1,
`Id` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
The table above has foreign key Id to localtexts.Id. And when I need to get word on English I do:
SELECT localtexts.text,
composes.status
FROM composes
LEFT JOIN localtexts ON composes.Id = localtexts.Id
WHERE localtexts.Lang = 'en'.
I'm concerned in performance this decision when there are a lot of tables for join with localtexts.
You might find that adding the following index to the localtexts table would speed up the query:
CREATE INDEX idx ON localtexts (Lang, id, text);
This index covers the WHERE clause, join, and SELECT.
I have 3 tables as below:
CREATE TABLE `user_dummy` (
`user_id` INT(11) NOT NULL AUTO_INCREMENT,
`user_name` VARCHAR(50) NOT NULL,
`user_email` VARCHAR(100) NOT NULL,
PRIMARY KEY (`user_id`)
)
ENGINE=InnoDB
;
CREATE TABLE `user_role` (
`user_role_id` INT(11) NOT NULL AUTO_INCREMENT,
`user_role_name` VARCHAR(255) NULL DEFAULT NULL,
PRIMARY KEY (`user_role_id`)
)
ENGINE=InnoDB
;
CREATE TABLE `user` (
`user_seq` INT(11) NOT NULL AUTO_INCREMENT,
`user_id` INT(11) NOT NULL,
`user_name` VARCHAR(50) NOT NULL,
`user_email` VARCHAR(100) NOT NULL,
`user_role_id` INT(11) NOT NULL,
PRIMARY KEY (`user_seq`),
INDEX `FKh2wc2dtfdo8maylne7mgubowq` (`user_role_id`),
CONSTRAINT `FKh2wc2dtfdo8maylne7mgubowq` FOREIGN KEY (`user_role_id`) REFERENCES `user_role` (`user_role_id`) ON UPDATE CASCADE ON DELETE CASCADE
)
ENGINE=InnoDB
;
I have created after insert trigger on user table.
i.e., when I insert 1 record into user_dummy table, it will insert records into table user table with all mappings of user_role.
trigger:
CREATE TRIGGER `user_dummy_after_insert` AFTER INSERT ON `user_dummy` FOR EACH ROW BEGIN
INSERT INTO user(user_id, user_name, user_email, user_role_id)
SELECT NEW.user_id, NEW.user_name, NEW.user_email, user_role_id
FROM user_role;
END
Above trigger is able to insert records into user table but the auto_increment value is incremented by 1 after each user_role record.
If you observe user_seq 3 is missing. And after inserting 4 records, auto_increment value set by trigger as 7.
How to fix this ?
Just an alternative: Better you could use the count function to count the total existing records and then increase it by one and assign according as. If you are interested to preserve the insertion sequence.
I have a problem counting ratings in SQL. This is what my data looks like:
data
CREATE TABLE `restaurant` (
`id_restaurant` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id_restaurant`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1;
insert into `restaurant`(`id_restaurant`,`name`) values (1,'Mc Donald');
insert into `restaurant`(`id_restaurant`,`name`) values (2,'KFC');
CREATE TABLE `user` (
`id_user` int(11) NOT NULL AUTO_INCREMENT,
`userName` varchar(50) DEFAULT NULL,
PRIMARY KEY (`id_user`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=latin1;
insert into `user`(`id_user`,`userName`) values (1,'Audey');
CREATE TABLE `factors` (
`factor_id` int(11) NOT NULL AUTO_INCREMENT,
`factor_clean` int(11) NOT NULL DEFAULT '0',
`factor_delicious` int(11) NOT NULL DEFAULT '0',
`id_restaurant` int(11) DEFAULT NULL,
`id_user` int(11) DEFAULT NULL,
PRIMARY KEY (`factor_id`),
KEY `id_restaurant` (`id_restaurant`),
KEY `id_user` (`id_user`),
CONSTRAINT `factors_ibfk_1` FOREIGN KEY (`id_restaurant`) REFERENCES `restaurant` (`id_restaurant`),
CONSTRAINT `factors_ibfk_2` FOREIGN KEY (`id_user`) REFERENCES `user` (`id_user`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1;
insert into `factors`(`factor_id`,`factor_clean`,`factor_delicious`,`id_restaurant`,`id_user`) values (1,1,5,1,1);
insert into `factors`(`factor_id`,`factor_clean`,`factor_delicious`,`id_restaurant`,`id_user`) values (2,0,5,1,1);
insert into `factors`(`factor_id`,`factor_clean`,`factor_delicious`,`id_restaurant`,`id_user`) values (3,1,5,1,1);
insert into `factors`(`factor_id`,`factor_clean`,`factor_delicious`,`id_restaurant`,`id_user`) values (4,3,3,1,1);
And the result should be like this, Show all ratings (1,2,3,4,5) and their count from the fields rating_clean, rating_delicious, and rating_clean
Thanks for your help.
but the result i get
SELECT COUNT(`factor_clean`+`factor_delicious`),'1' AS rating_1 FROM `factors` WHERE 1 GROUP BY `id_restaurant`
result not should like this
the result should not like that,
my question is, how to select just factor_clean and factor_delicious where factor_clean =1 and factor_delicious = 1
Use union all to unpivot the data and then aggregate:
select id_restaurant, rating, count(*)
from ((select r.id_restaurant, r.rating_clean as rating, r.date
from ratings r
) union all
(select r.id_restaurant, r.rating_delicious, r.date
from ratings r
) union all
(select r.id_restaurant, r.rating_clean2, r.date
from ratings r
)
) r
group by id_restaurant, rating
order by id_restaurant, rating;
For example this is solution for table with colums rating_delicious and rating_clean (only one!):
First of all you should create additional table, I called it factors:
CREATE TABLE `factors` (
`factor_id` int(11) NOT NULL AUTO_INCREMENT,
`factor_clean` int(11) NOT NULL DEFAULT '0',
`factor_delicious` int(11) NOT NULL DEFAULT '0',
PRIMARY KEY (`factor_id`)
)
Next add two records:
INSERT INTO `factors` (`factor_id`, `factor_clean`, `factor_delicious`) VALUES (NULL, '1', '0'), (NULL, '0', '1');
Now you can join this tables and get results:
SELECT x.id_restaurant
, (x.rating_clean * f.factor_clean) + (x.rating_delicious * f.factor_delicious) AS rating
, count(*)
FROM your_table x
JOIN factors f
WHERE 1
GROUP
BY x.id_restaurant
, rating
In order to use next colum (rating_third), you should and column factor_third to factors, insert new row with 1 in this column and finally add something like your_table.rating_third*factors.factor_third to sum in SELECT
I have three tables :- category ,employee and user_access_permission . I want to create a trigger that will fire when new category is added , insert values in user_access_permission for each employee id .default value for user_access is 0.
Category table :-
CREATE TABLE IF NOT EXISTS `categories` (
`category_id` int(11) NOT NULL AUTO_INCREMENT,
`category_name` varchar(100) NOT NULL,
`section_id` int(11) NOT NULL,
UNIQUE KEY `category_id` (`category_id`),
UNIQUE KEY `category_name` (`category_name`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;
Employee table :-
CREATE TABLE IF NOT EXISTS `employee` (
`employee_id` int(11) NOT NULL AUTO_INCREMENT,
`emp_pass` varchar(50) NOT NULL,
`email` varchar(100) NOT NULL,
PRIMARY KEY (`employee_id`),
UNIQUE KEY `email_UNIQUE` (`email`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT=' ' AUTO_INCREMENT=1;
User Access Permission Table :-
CREATE TABLE IF NOT EXISTS `user_access_permission` (
`uap_id` int(10) NOT NULL AUTO_INCREMENT,
`section_id` int(10) NOT NULL,
`category_id` int(10) NOT NULL,
`employee_id` int(10) NOT NULL,
`access_level` int(10) NOT NULL DEFAULT '0',
PRIMARY KEY (`uap_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1;
I am writing trigger like this :-
CREATE TRIGGER update_permssion_on_add_category
AFTER INSERT
ON categories FOR EACH ROW
insert into user_access_permission(section_id,category_id,employee_id,access_level) select(new.section_id,new.category_id,employee_id,0) from employee
But I don't get things right. Please Help
You have
select(new.section_id,new.category_id,employee_id,0) from employee
but section_id and category_id come from the category table.
I would suggest changing it to be 'from category' but the problem then is where do you get the employee_id number from? It's not anywhere in the original insert statement for the category table. Unless you decide to have it be some default value every time the trigger is fired.
This is the query (a search query basically, based on tags):-
select
SUM(DISTINCT(ttagrels.id_tag in (2105,2120,2151,2026,2046) )) as key_1_total_matches, td.*, u.*
from Tutors_Tag_Relations AS ttagrels
Join Tutor_Details AS td ON td.id_tutor = ttagrels.id_tutor
JOIN Users as u on u.id_user = td.id_user
where (ttagrels.id_tag in (2105,2120,2151,2026,2046)) group by td.id_tutor HAVING key_1_total_matches = 1
And following is the database dump needed to execute this query:-
CREATE TABLE IF NOT EXISTS `Users` (
`id_user` int(10) unsigned NOT NULL auto_increment,
`id_group` int(11) NOT NULL default '0',
PRIMARY KEY (`id_user`),
KEY `Users_FKIndex1` (`id_group`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=730 ;
INSERT INTO `Users` (`id_user`, `id_group`) VALUES
(303, 1);
CREATE TABLE IF NOT EXISTS `Tutor_Details` (
`id_tutor` int(10) unsigned NOT NULL auto_increment,
`id_user` int(10) NOT NULL default '0',
PRIMARY KEY (`id_tutor`),
KEY `Users_FKIndex1` (`id_user`),
KEY `id_user` (`id_user`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=58 ;
INSERT INTO `Tutor_Details` (`id_tutor`, `id_user`) VALUES
(26, 303);
CREATE TABLE IF NOT EXISTS `Tags` (
`id_tag` int(10) unsigned NOT NULL auto_increment,
`tag` varchar(255) default NULL,
PRIMARY KEY (`id_tag`),
UNIQUE KEY `tag` (`tag`),
KEY `id_tag` (`id_tag`),
KEY `tag_2` (`tag`),
KEY `tag_3` (`tag`),
KEY `tag_4` (`tag`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2957 ;
INSERT INTO `Tags` (`id_tag`, `tag`) VALUES
(2026, 'Brendan.\nIn'),
(2046, 'Brendan.'),
(2105, 'Brendan'),
(2120, 'Brendan''s'),
(2151, 'Brendan)');
CREATE TABLE IF NOT EXISTS `Tutors_Tag_Relations` (
`id_tag` int(10) unsigned NOT NULL default '0',
`id_tutor` int(10) unsigned default NULL,
`tutor_field` varchar(255) default NULL,
`cdate` timestamp NOT NULL default CURRENT_TIMESTAMP,
`udate` timestamp NULL default NULL,
KEY `Tutors_Tag_Relations` (`id_tag`),
KEY `id_tutor` (`id_tutor`),
KEY `id_tag` (`id_tag`),
KEY `id_tutor_2` (`id_tutor`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO `Tutors_Tag_Relations` (`id_tag`, `id_tutor`, `tutor_field`, `cdate`, `udate`) VALUES
(2105, 26, 'firstname', '2010-06-17 17:08:45', NULL);
ALTER TABLE `Tutors_Tag_Relations`
ADD CONSTRAINT `Tutors_Tag_Relations_ibfk_2` FOREIGN KEY (`id_tutor`) REFERENCES `Tutor_Details` (`id_tutor`) ON DELETE NO ACTION ON UPDATE NO ACTION,
ADD CONSTRAINT `Tutors_Tag_Relations_ibfk_1` FOREIGN KEY (`id_tag`) REFERENCES `Tags` (`id_tag`) ON DELETE NO ACTION ON UPDATE NO ACTION;
What the query does?
This query actually searches tutors which contain "Brendan"(as their name or biography or something). The id_tags 2105,2120,2151,2026,2046 are nothing but the tags which are LIKE "%Brendan%".
My question is :-
1.In the explain of this query, the reference column shows NULL for ttagrels, but there are possible keys (Tutors_Tag_Relations,id_tutor,id_tag,id_tutor_2). So, why is no key being taken. How to make the query take references. Is it possible at all?
2. The other two tables td and u are using references. Any indexing needed in those? I think not.
Check the explain query output here
http://www.test.examvillage.com/explain.png
Don't analyze performance of database with single record in table. Create at least 100 records.