Mysql how to join tables more than two - mysql

I have problem with my query,
I have tables below:
CREATE TABLE IF NOT EXISTS `klik_zona` (
`kode_zona` int(10) unsigned NOT NULL,
`klik` int(10) unsigned NOT NULL,
PRIMARY KEY (`kode_zona`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `klik_zona` (`kode_zona`, `klik`) VALUES
(1, 45);
CREATE TABLE IF NOT EXISTS `tampil_zona` (
`kode_zona` int(10) unsigned NOT NULL,
`tanggal` date NOT NULL,
`tampil` int(10) unsigned NOT NULL,
PRIMARY KEY (`kode_zona`,`tanggal`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `tampil_zona` (`kode_zona`, `tanggal`, `tampil`) VALUES
(1, '2014-03-16', 100),
(1, '2014-03-17', 23);
CREATE TABLE IF NOT EXISTS `zona_iklan` (
`kode_zona` int(10) unsigned NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`kode_zona`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=4 ;
INSERT INTO `zona_iklan` (`kode_zona`) VALUES
(1),
(2),
(3);
I have query:
SELECT z.kode_zona, SUM( tz.tampil ) , SUM( kz.klik )
FROM zona_iklan z
LEFT JOIN tampil_zona tz ON tz.kode_zona = z.kode_zona
LEFT JOIN klik_zona kz ON kz.kode_zona = z.kode_zona
GROUP BY z.kode_zona
but it give result:
kode_zona SUM(tz.tampil) SUM(kz.klik)
1 123 90
2 NULL NULL
3 NULL NULL
I want get result:
kode_zona SUM(tz.tampil) SUM(kz.klik)
1 123 45
2 NULL NULL
3 NULL NULL
please help me.. how to make query so that I get result that I hope it..
thanks,

In your example you join two records from tampil_zona on to one record from zona_iklan, which essentially causes that one record to duplicate. Then you are joining one record in klik_zona on to both of those duplicated records, causing the doubling of results that you want to avoid.
Instead, you need to aggregate the records before you join them, to ensure that you are always joining the records 1-to-1.
SELECT
z.kode_zona, tz.tampil, kz.klik
FROM
zona_iklan AS z
LEFT JOIN
(SELECT kode_zona, SUM(tampil) AS tampil FROM tampil_zona GROUP BY kode_zona) AS tz
ON tz.kode_zona = z.kode_zona
LEFT JOIN
(SELECT kode_zona, SUM(klik) AS klik FROM klik_zona GROUP BY kode_zona) AS kz
ON kz.kode_zona = z.kode_zona

Try removing the GROUP BY and look at the result. You will see that there are two records with kode_zona = 1. This because there are two records in tampil_zona matching that id. You could divide by count(*) but that seems futile. You probably want to think about how to modify the join.

Related

Max from joined table based on value from first table

I have 2 tables.
First holds job details, second one the history of those job runs. First one also contains job period, per customer which is minimum time to wait before running next job for same customer. The time comparison needs to happen on started_on field of second table.
I need to find out the job ids to run next.
Schemas
job_details table
CREATE TABLE `job_details` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`customer_id` varchar(128) NOT NULL,
`period_in_minutes` int(11) unsigned NOT NULL,
`status` enum('ACTIVE','INACTIVE','DELETED') DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
job_run_history table
CREATE TABLE `job_run_history` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`job_id` int(10) unsigned NOT NULL,
`started_on` timestamp NULL DEFAULT NULL,
`status` enum('STREAMING','STREAMED','UPLOADING','UPLOADED','NO_RECORDS','FAILED') DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `fk_job_id` (`job_id`),
CONSTRAINT `fk_job_id` FOREIGN KEY (`job_id`) REFERENCES `job_details` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
Sample data for job_details table:
INSERT INTO `job_details` (`id`, `customer_id`, `period_in_minutes`, `status`)
VALUES
(1, 'cust1', 1, 'ACTIVE'),
(2, 'cust2', 1, 'ACTIVE'),
(3, 'cust3', 2, 'ACTIVE');
Sample data for job_run_history table:
INSERT INTO `job_run_history`(`job_id`, `started_on`, `status`)
VALUES
(1, '2021-07-01 14:38:00', 'UPLOADED'),
(2, '2021-07-01 14:37:55', 'UPLOADED');
Expected output (When run at 2021-07-01 14:38:56):
id
2,3
id => 1 did NOT get selected because the last job started within last 1 minute
id => 2 DID get selected because the last job started more than last 1 minute ago
id => 3 DID get selected because it has no run history
I have tried this, but this doesn't compare with max of start_time, hence, doesn't work:
select jd.id, max(jrh.started_on) from job_details jd
left join job_run_history jrh on jrh.job_id=jd.id
where
jd.status='ACTIVE'
and (jrh.status is null or jrh.status not in ('STREAMING','STREAMED','UPLOADING'))
and (jrh.`started_on` is null or jrh.`started_on` < date_sub(now(), interval jd.`period_in_minutes`*60 second))
group by jd.id;
MySql Version: 5.7.34
Any help please? Thanks in advance..
I'd prefer to use UNION ALL (it must be more fast than one complex query):
-- the subquery for the rows which have matched ones in 2nd table
SELECT t1.id
FROM job_details t1
JOIN job_run_history t2 ON t1.id = t2.job_id
WHERE t1.status = 'ACTIVE'
AND t2.status not in ('STREAMING','STREAMED','UPLOADING')
AND CURRENT_TIMESTAMP - INTERVAL t1.period_in_minutes MINUTE > t2.started_on
UNION ALL
-- the subquery for the rows which have no matched ones in 2nd table
SELECT id
FROM job_details t1
WHERE NOT EXISTS ( SELECT NULL
FROM job_run_history t2
WHERE t1.id = t2.job_id )
AND status = 'ACTIVE';
https://dbfiddle.uk/?rdbms=mysql_5.7&fiddle=8dcad95bf43ce711fdf40deda627e879
select jd.id from job_details jd
left join job_run_history jrh on jd.id= jrh.job_id
where jd.status = 'ACTIVE'
group by jd.id
having
max(jrh.started_on) < current_timestamp - interval max(jd.period_in_minutes) minute
or
max(jrh.id) is null
I'm not sure what's this filter about since you didn't explain it in your question so I didn't put it in the query: jrh.status not in ('STREAMING','STREAMED','UPLOADING'). However, I'm sure you can implement it in the query I posted.

Update statement causes fields to be updated with NULL or maximum value

If you had to pick one of the two following queries, which would you choose and why:
UPDATE `table1` AS e
SET e.points = e.points+(
SELECT points FROM `table2` AS ep WHERE e.cardnbr=ep.cardnbr);
or:
UPDATE `table1` AS e
INNER JOIN
(
SELECT points, cardnbr
FROM `table2`
) AS ep ON (e.cardnbr=ep.cardnbr)
SET e.points = e.points+ep.points;
Tables' definitions:
CREATE TABLE `table1` (
`cardnbr` int(10) DEFAULT NULL,
`name` varchar(50) DEFAULT NULL,
`points` decimal(7,3) DEFAULT '0.000',
`email` varchar(50) NOT NULL DEFAULT 'user#company.com',
`id` int(11) NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=25205 DEFAULT CHARSET=latin1$$
CREATE TABLE `table2` (
`cardnbr` int(10) DEFAULT NULL,
`id` int(11) NOT NULL AUTO_INCREMENT,
`points` decimal(7,3) DEFAULT '0.000',
PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=4 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci$$
UPDATE: BOTH are causing problems the first is causing non matched rows to update into NULL.
The second is causing them to update into the max value 999.9999 (decimal 7,3).
PS the cardnbr field is NOT a key
I prefer the second one..reason for that is
When using JOIN the databse can create an execution plan that is better for your query and save time whereas subqueries (like your first one ) will run all the queries and load all the datas which may take time.
i think subqueries is easy to read but performance wise JOIN is faster...
First, the two statements are not equivalent, as you found out yourself. The first one will update all rows of table1, putting NULL values for those rows that have no related rows in table2.
So the second query looks better because it doesn't update all rows of table1. It could be written in a more simpel way, like this though:
UPDATE table1 AS e
INNER JOIN table2 AS ep
ON e.cardnbr = ep.cardnbr
SET e.points = e.points + ep.points ;
So, the 2nd query would be the best to use, if cardnbr was the primary key of table2. Is it?
If it isn't, then which values from table2 should be used for the update of table1 (added to points)? All of them? You could use this:
UPDATE table1 AS e
INNER JOIN
( SELECT SUM(points) AS points, cardnbr
FROM table2
GROUP BY cardnbr
) AS ep ON e.cardnbr = ep.cardnbr
SET
e.points = e.points + ep.points ;
Just one of them? That would require some other derived table, depending on what you want.

Counting records in normalized table

Older questions seen
Counting one table of records for matching records of another table
MySQL Count matching records from multiple tables
Count records from two tables grouped by one field
Table(s) Schema
Table entries having data from 2005-01-25
CREATE TABLE `entries` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`ctg` VARCHAR(15) NOT NULL,
`msg` VARCHAR(200) NOT NULL,
`nick` VARCHAR(30) NOT NULL,
`date` DATETIME NOT NULL,
PRIMARY KEY (`id`),
INDEX `msg` (`msg`),
INDEX `date` (`date`)
)
COLLATE='utf8_general_ci'
ENGINE=MyISAM;
Child table magnets with regular data from 2011-11-08(There might be a few entries from before that)
CREATE TABLE `magnets` (
`id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
`eid` INT(10) UNSIGNED NOT NULL,
`tth` CHAR(39) NOT NULL,
`size` BIGINT(20) UNSIGNED NOT NULL DEFAULT '0',
`nick` VARCHAR(30) NOT NULL DEFAULT 'hjpotter92',
`date` DATETIME NOT NULL,
PRIMARY KEY (`id`),
UNIQUE INDEX `eid_tth` (`eid`, `tth`),
INDEX `entriedID` (`eid`),
INDEX `tth_size` (`tth`, `size`)
)
COLLATE='utf8_general_ci'
ENGINE=MyISAM;
Question
I want to get the count of total number of entries by any particular nick(or user) entered in either of the table.
One of the entry in entries is populated at the same time as magnets and the subsequent entries of magnets can be from the same nick or different.
My Code
Try 1
SELECT `e`.id, COUNT(1), `e`.nick, `m`.nick
FROM `entries` `e`
INNER JOIN `magnets` `m`
ON `m`.`eid` = `e`.id
GROUP BY `e`.nick
Try 2
SELECT `e`.id, COUNT(1), `e`.nick
FROM `entries` `e`
GROUP BY `e`.nick
UNION ALL
SELECT `m`.eid, COUNT(1), `m`.nick
FROM `magnets` `m`
GROUP BY `m`.nick
The second try is generating some relevant outputs, but it contains double entries for all the nick which appear in both tables.
Also, I don't want to count twice, those entries/magnets which were inserted in the first query. Which is what the second UNION statement is doing. It takes in all the values from both tables.
SQL Fiddle link
Here is the link to a SQL Fiddle along with randomly populated entries.
I really hope someone can guide me through this. If it's any help, I will be using PHP for final display of data. So, my last resort would be to nest loops in PHP for the counting(which I am currently doing).
Desired output
The output that should be generated on the fiddle should be:
************************************************
** Nick ||| Count **
************************************************
** Nick1 ||| 10 **
** Nick2 ||| 9 **
** Nick3 ||| 6 **
** Nick4 ||| 10 **
************************************************
There might be a more efficient way but this works if I understand correctly:
SELECT SUM(cnt), nick FROM
(SELECT count(*) cnt, e.nick FROM entries e
LEFT JOIN magnets m ON (e.id=m.eid AND e.nick=m.nick)
WHERE eid IS NULL GROUP BY e.nick
UNION ALL
SELECT count(*) cnt, nick FROM magnets m GROUP BY nick) u
GROUP BY nick

MySQL Select Records from 2 not-related Tables Ordering by Timestamp

I'd like to collect data from 2 different mysql tables ordering the result by a timestamp but without merging the columns of the 2 tables in a single row.
T_ONE(one_id,one_someinfo,one_ts)
T_TWO(two_id,two_otherinfo,two_ts)
Notice that the field two_otherinfo is not the same as one_someinfo, the only columns in common are id and timestamp.
The result should be a mix of the two tables ordered by the timestamp but each row, depending on the timestamp, should contain only the respective columns of the table.
For example, if the newest record comes from T_TWO that row should have the T_ONE one_someinfo column empty.
I just need to order the latest news from T_ONE and the latest messages posted on T_TWO so the tables are not related. I'd like to avoid using 2 queries and then merging and ordering the results by timestamp with PHP. Does anyone know a solution to this? Thanks in advance
This is the structure of the table
CREATE TABLE `posts` (
`id` int(10) unsigned NOT NULL auto_increment,
`fromid` int(10) NOT NULL,
`toteam` int(10) NOT NULL,
`banned` tinyint(1) NOT NULL default '0',
`replyid` int(15) default NULL,
`cont` mediumtext NOT NULL,
`timestamp` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;
CREATE TABLE `stars` (
`id` int(10) unsigned NOT NULL auto_increment,
`daynum` int(10) NOT NULL,
`userid` int(10) NOT NULL,
`vote` tinyint(2) NOT NULL default '3',
`timestamp` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;
INSERT INTO `posts` (`fromid`, `toteam`, `banned`, `replyid`, `cont`, `timestamp`) VALUES(5, 12, 0, 0, 'mess posted#1', 1222222220);
INSERT INTO `posts` (`fromid`, `toteam`, `banned`, `replyid`, `cont`, `timestamp`) VALUES(5, 12, 0, 0, 'mess posted#2', 1222222221);
INSERT INTO `posts` (`fromid`, `toteam`, `banned`, `replyid`, `cont`, `timestamp`) VALUES(5, 12, 0, 0, 'mess posted#3', 1222222223);
INSERT INTO `stars` (`daynum`, `userid`, `vote`, `timestamp`) VALUES(3, 160, 4, 1222222222);
INSERT INTO `stars` (`daynum`, `userid`, `vote`, `timestamp`) VALUES(4, 180, 3, 1222222224);
The result ordering by timestamp DESC should be the second record of table stars with timestamp 1222222224 then the third record of table posts with timestamp 1222222223 and following... Since the tables have got different fields from each other, the first row of the result should contain the columns of the table stars while the columns of table posts should be empty.
The columns of a UNION must be the same name and datatype on every row. In fact, declare column aliases in the first UNION subquery, because it ignores any attempt to rename the column in subsequent subqueries.
If you need the columns from the two subqueries to be different, put in NULL as placeholders. Here's an example, fetching the common columns id and timestamp, and then fetching one custom column from each of the subqueries.
(SELECT p.id, p.timestamp AS ts, p.fromid, NULL AS daynum FROM posts)
UNION
(SELECT s.id, s.timestamp, NULL, s.daynum, FROM stars)
ORDER BY ts DESC
Also put the subqueries in parentheses, so the last ORDER BY applies to the whole result of the UNION, not just to the last subquery.
SELECT one_id AS id, one_someinfo AS someinfo, one_ts AS ts
UNION
SELECT two_id AS id, two_someinfo AS someinfo, two_ts AS ts
ORDER BY ts
SELECT one_id AS id
, one_someinfo AS one_someinfo
, NULL AS two_someinfo
, one_ts AS ts
FROM t_ONE
UNION ALL
SELECT two_id
, NULL
, two_someinfo
, two_ts
FROM t_TWO
ORDER BY ts

MySQL query killing my server

Looking at this query there's got to be something bogging it down that I'm not noticing. I ran it for 7 minutes and it only updated 2 rows.
//set product count for makes
$tru->query->run(array(
'name' => 'get-make-list',
'sql' => 'SELECT id, name FROM vehicle_make',
'connection' => 'core'
));
while($tempMake = $tru->query->getArray('get-make-list')) {
$tru->query->run(array(
'name' => 'update-product-count',
'sql' => 'UPDATE vehicle_make SET product_count = (
SELECT COUNT(product_id) FROM taxonomy_master WHERE v_id IN (
SELECT id FROM vehicle_catalog WHERE make_id = '.$tempMake['id'].'
)
) WHERE id = '.$tempMake['id'],
'connection' => 'core'
));
}
I'm sure this query can be optimized to perform better, but I can't think of how to do it.
vehicle_make = 45 rows
taxonomy_master = 11,223 rows
vehicle_catalog = 5,108 rows
All tables have appropriate indexes
UPDATE: I should note that this is a 1-time script so overhead isn't a big deal as long as it runs.
CREATE TABLE IF NOT EXISTS `vehicle_make` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(32) NOT NULL,
`product_count` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=46 ;
CREATE TABLE IF NOT EXISTS `taxonomy_master` (
`product_id` int(10) NOT NULL,
`v_id` int(10) NOT NULL,
`vehicle_requirement` varchar(255) DEFAULT NULL,
`is_sellable` enum('True','False') DEFAULT 'True',
`programming_override` varchar(25) DEFAULT NULL,
PRIMARY KEY (`product_id`,`v_id`),
KEY `idx2` (`product_id`),
KEY `idx3` (`v_id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
CREATE TABLE IF NOT EXISTS `vehicle_catalog` (
`v_id` int(10) NOT NULL,
`id` int(11) NOT NULL,
`v_make` varchar(255) NOT NULL,
`make_id` int(11) NOT NULL,
`v_model` varchar(255) NOT NULL,
`model_id` int(11) NOT NULL,
`v_year` varchar(255) NOT NULL,
PRIMARY KEY (`v_id`,`v_make`,`v_model`,`v_year`),
UNIQUE KEY `idx` (`v_make`,`v_model`,`v_year`),
UNIQUE KEY `idx2` (`v_id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
Update: The successful query to get what I needed is here....
SELECT
m.id,COUNT(t.product_id) AS CountOf
FROM taxonomy_master t
INNER JOIN vehicle_catalog v ON t.v_id=v.id
INNER JOIN vehicle_make m ON v.make_id=m.id
GROUP BY m.id;
without the tables/columns this is my best guess from reverse engineering the given queries:
UPDATE m
SET product_count =COUNT(t.product_id)
FROM taxonomy_master t
INNER JOIN vehicle_catalog v ON t.v_id=v.id
INNER JOIN vehicle_make m ON v.make_id=m.id
GROUP BY m.name
The given code loops over each make, and then runs a query the counts for each. My answer just does them all in one query and should be a lot faster.
have an index for each of these:
vehicle_make.id cover on name
vehicle_catalog.id cover make_id
taxonomy_master.v_id
EDIT
give this a try:
CREATE TEMPORARY TABLE CountsOf (
id int(11) NOT NULL
, CountOf int(11) NOT NULL DEFAULT 0.00
);
INSERT INTO CountsOf
(id, CountOf )
SELECT
m.id,COUNT(t.product_id) AS CountOf
FROM taxonomy_master t
INNER JOIN vehicle_catalog v ON t.v_id=v.id
INNER JOIN vehicle_make m ON v.make_id=m.id
GROUP BY m.id;
UPDATE taxonomy_master,CountsOf
SET taxonomy_master.product_count=CountsOf.CountOf
WHERE taxonomy_master.id=CountsOf.id;
instead of using nested query ,
you can separated this query to 2 or 3 queries,
and in php insert the result of the inner query to the out query ,
its faster !
#haim-evgi Separating the queries will not increase the speed significantly, it will just shift the load from the DB server to the Web server and create overhead of moving data between the two servers.
I am not sure with the appropriate indexes you run such query 7 minutes. Could you please show the table structure of the tables involved in these queries.
Seems like you need the following indices:
INDEX BTREE('make_id') on vehicle_catalog
INDEX BTREE('v_id') on taxonomy_master