Table structure and data (I know data in IP/domain fields might not make much sense, but this is for illustration purposes):
rec_id | account_id | product_id | ip | domain | some_data
----------------------------------------------------------------------------
1 | 1 | 1 | 192.168.1.1 | 127.0.0.1/test | abc
2 | 1 | 1 | 192.168.1.1 | 127.0.0.1/other | xyz
3 | 1 | 1 | 192.168.1.2 | 127.0.0.1/test | ooo
Table has unique index ip_domain combined from ip and domain fields (so records with identical values in both fields can't exist).
In each case I know values for account_id, product_id, ip, domain fields, and I need to get other rows that have the SAME account_id, product_id values and one (or both) of ip, domain values are DIFFERENT.
Example: I know that account_id=1, product_id=1, ip=192.168.1.1, domain=127.0.0.1/test (so it matches rec_id 1), I need to select records with IDs 2 and 3 (because record 2 has different domain and record 3 has different ip).
So, I used query:
SELECT * FROM table WHERE
account_id='1' AND product_id='1' AND ip!='192.168.1.1' AND domain!='127.0.0.1/test'
Of course, it returned 0 rows. Looked at mysql multiple where and where not in and wrote:
SELECT * FROM table WHERE
account_id='1' AND product_id='1' AND installation_ip NOT IN ('192.168.1.1') AND installation_domain NOT IN ('127.0.0.1/test')
My guess is that this query is identical (just formatted different way), so 0 rows again. Found some more examples too, but none worked in my case.
The syntax is correct, but you're using the wrong logical operation
SELECT *
FROM table
WHERE account_id='1' AND product_id='1' AND
(ip != '192.168.1.1' OR domain != '127.0.0.1/test')
Select * from table
Where ROWID <> myRowid
And account_id = '1'
And product_id = '1';
myRowid is the unique id given by your dbms to each record, in this case you need to retrieve it with your select statement and then pass it back when using this select. This will return all the rows with account_id = 1 and product_id = 1 except the one you have selected.
If your inputs are not defined/or if you want list then you may be look at Group By clause. Also, you may look at group_concat
Query would be something like:
SELECT ACCOUNT_ID, PRODUCT_ID, GROUP_CONCAT(DISTINCT IP||'|'||DOMAIN, ','), COUNT(1)
FROM TABLE
GROUP BY ACCOUNT_ID, PRODUCT_ID
P.S.: I dont have mysql installed hence the query syntax is not verified
Related
I have a mysql table called "projects" with a single field containing CSV lists of project Ids. Assume that I cannot change the table structure.
I need a query that will allow me to quickly retrieve a count of rows that contain a particular project id, for example:
select count(*) from projects where '4' in (project_ids);
This returns just 1 result, which is incorrect (should be 3 results), but I think that it illustrates what I'm attempting to do.
CREATE TABLE `projects` (
`project_ids` varchar(255) DEFAULT NULL
);
INSERT INTO `projects` (`project_ids`)
VALUES
('1,2,4'),
('1,2'),
('4'),
('4,5,2'),
('1,2,5');
I was hoping that there might be a simple mysql function that would achieve this so that I don't have to anything complex sql-wise.
You could use this approach:
SELECT COUNT(*)
FROM projects
WHERE CONCAT(',', project_ids, ',') LIKE '%,4,%';
Or use FIND_IN_SET for a built-in way:
SELECT COUNT(*)
FROM projects
WHERE FIND_IN_SET('4', project_ids) > 0;
But, as to that which Gordon's comment alludes, a much better table design would be to have a junction table which relates a primary key in one table to all projects in another table. That junction table, based off your sample data, would look like this:
PK | project_id
1 | 1
1 | 2
1 | 4
2 | 1
2 | 2
3 | 4
4 | 4
4 | 5
4 | 2
5 | 1
5 | 2
5 | 5
With this design, if you wanted to find the count of PK's having a project_id of 4, you would only need a much simpler (and sargable) query:
SELECT COUNT(*)
FROM junction_table
WHERE project_id = 4;
You would need to use a like condition as follows
select count(*)
from projects
where concat(',',project_ids,',') like '%,4,%';
Briefly: database imported from foreign source, so I cannot prevent duplicates, I can only prune and clean the database.
Foreign db changes daily, so, I want to automate the pruning process.
It resides on:
MariaDB v10.4.6 managed predominantly by phpMyadmin GUI v4.9.0.1 (both pretty much up to date as of this writing).
This is a radio browsing database.
It has multiple columns, but for me there are only few important:
StationID (it is unique entry number, thus db does not consider new entries as duplicates, all of them are unique because of this primary key)
There are no row numbers.
Name, url, home-page, country, etc
I do want to remove multiple url duplicated entries base on:
duplicate url has country to it, but some country values are NULL (=empty)
so I do want remove all duplicates except one containing country name, if there is one entry with it, if there is none, just one url, regardless of name (names are multilingual, so some duplicated urls have also various names, which I do not care for.
StationID (unique number, but not consecutive, also this is primary db key)
Name (variable, least important)
url (variable, but I do want to remove the duplicates)
country (variable, frequently NULL/empty, I want to eliminate those with empty entries as much as possible, if possible)
One url has to stay by any means (not to be deleted)
I have tried multitude of queries, some work for SELECT, but do NOT for DELETE, some hang my machine when executed. Here are some queries I tried (remember I use MariaDB, not oracle, or ms-sql)
SELECT * from `radio`.`Station`
WHERE (`radio`.`Station`.`Url`, `radio`.`Station`.`Name`) IN (
SELECT `radio`.`Station`.`Url`, `radio`.`Station`.`Name`
FROM `radio`.`Station`
GROUP BY `radio`.`Station`.`Url`, `radio`.`Station`.`Name`
HAVING COUNT(*) > 1)
This one should show all entries (not only one grouped), but this query hangs my machine
This query gets me as close as possible:
SELECT *
FROM `radio`.`Station`
WHERE `radio`.`Station`.`StationID` NOT IN (
SELECT MAX(`radio`.`Station`.`StationID`)
FROM `radio`.`Station`
GROUP BY `radio`.`Station`.`Url`,`radio`.`Station`.`Name`,`radio`.`Station`.`Country`)
However this query lists more entries:
SELECT *, COUNT(`radio`.`Station`.`Url`) FROM `radio`.`Station` GROUP BY `radio`.`Station`.`Name`,`radio`.`Station`.`Url` HAVING (COUNT(`radio`.`Station`.`Url`) > 1);
But all of these queries group them and display only one row.
I also tried UNION, INNER JOIN, but failed.
WITH cte AS..., but phpMyadmin does NOT like this query, and mariadb cli also did not like it.
I also tried something of this kind, published at oracle blog, which did not work, and I really had no clue what was what in this function:
select *
from (
select f.*,
count(*) over (
partition by `radio`.`Station`.`Url`, `radio`.`Station`.`Name`
) ct
from `radio`.`Station` f
)
where ct > 1
I did not know what f.* was, query did not like ct.
Given
drop table if exists radio;
create table radio
(stationid int,name varchar(3),country varchar(3),url varchar(3));
insert into radio values
(1,'aaa','uk','a/b'),
(2,'bbb','can','a/b'),
(3,'bbb',null,'a/b'),
(4,'bbb',null,'b/b'),
(5,'bbb',null,'b/b');
You could give the null countries a unique value (using coalesce), fortunately stationid is unique so:
select t.stationid,t.name,t.country,t.url
from radio t
join
(select url,max(coalesce(country,stationid)) cntry from radio t group by url) s
on s.url = t.url and s.cntry= coalesce(t.country,t.stationid);
Yields
+-----------+------+---------+------+
| stationid | name | country | url |
+-----------+------+---------+------+
| 1 | aaa | uk | a/b |
| 5 | bbb | NULL | b/b |
+-----------+------+---------+------+
2 rows in set (0.00 sec)
Translated to a delete
delete t from radio t
join
(select url,max(coalesce(country,stationid)) cntry from radio t group by url) s
on s.url = t.url and s.cntry <> coalesce(t.country,t.stationid);
MariaDB [sandbox]> select * from radio;
+-----------+------+---------+------+
| stationid | name | country | url |
+-----------+------+---------+------+
| 1 | aaa | uk | a/b |
| 5 | bbb | NULL | b/b |
+-----------+------+---------+------+
2 rows in set (0.00 sec)
Fix 2 problems at once:
Dup rows already in table
Dup rows can still be put in table
Do this fore each table:
CREATE TABLE new LIKE real;
ALTER TABLE new ADD UNIQUE(x,y); -- will prevent future dups
INSERT IGNORE INTO new -- IGNORE dups
SELECT * FROM real;
RENAME TABLE real TO old, new TO real;
DROP TABLE old;
I'm going to implement a method on my own SQL. I have two tables in MySQL. Suppose that each row is updated in the FirstTable and the values of the rate and countView are variable, I'm trying to update them with the same command:
UPDATE FirstTable SET `countView`= `countView`+1,
`rate`=('$MyRate' + (`countView`-1)*`rate`)/`countView`
WHERE `productId`='$productId'
FirstTable:
productId | countView | rate | other column |
------------+-----------+------+-------------------+---
21 | 12 | 4 | anything |
------------+-----------+------+-------------------+---
22 | 18 | 3 | anything |
------------+-----------+------+-------------------+---
But in this way, a user can vote every time he wants to. So I tried to create a table with two columns productId and userID. Like below:
SecondTable:
productId | userID |
------------+---------------|
21 | 100001 |
------------+---------------|
22 | 100002 |
------------+---------------|
21 | 100001 |
------------+---------------|
21 | 100003 |
------------+---------------|
Now, as in the example given in the SecondTable, a user has given to a productId two vote. So I don't want both of these votes to be recorded.
Problems with this method:
The value of the counter is added to each vote.
I can not properly link the SecondTable and FirstTable to manage the update of the FirstTable.
Of course, this question may not be completely new, but I searched a lot to get the right answer. One of the questions from this site came through this method. Using this method, you can manage the update of a table. This method is as follows:
UPDATE `FirstTable` SET `countView`= `countView`+1,
`rate`=('$MyRate' + (`countView`-1)*`rate`)/`countView`
WHERE `productId`='$productId' IN ( SELECT DISTINCT productId, userID
FROM SecondTable)
But the next problem is that even when I use this command, I encounter the following error:
1241 - Operand should contain 1 column(s)
So thank you so much if you can guide me. And I'm sure my question is not duplicate... thank you again.
This fixes your specific syntax problem:
UPDATE FirstTable
SET countView = countView + 1,
rate = ($MyRate + (countView - 1) * rate) / countView
WHERE productId = $productId AND
productId IN (SELECT t2.productId FROM SecondTable t2);
But if two different users vote on the same product, FirstTable will be updated only once. It is unclear if that is intentional behavior or not.
Note that SELECT DISTINCT is not needed in the subquery.
The error is being generated because you can't return 2 fields in an "in" statement. You'll want to use group by:
Try:
IN ( SELECT DISTINCT productId FROM rating group by product, UserID)
Here's documentation to look over for mysql group by if you want: https://dev.mysql.com/doc/refman/5.7/en/group-by-handling.html
I'm trying to output a default row when there's no row found in the query.
This is a sample of my query:
SELECT
COALESCE(site, 'STE') as site,
instrument,
field
FROM Table1
WHERE site IN ('East', 'West')
AND DATE(tstamp) = "2016-09-07"
ORDER BY id desc
The output is
+------+------------+-------+
| site | instrument | field |
+------+------------+-------+
| West | 0 | 0 |
+------+------------+-------+
For the tsamp 2016-09-07 we have a row for the site "West" and there's no row for "East". I tried to search and found that I can use COALESCE and also tried IFNULL but I'm only getting the output above. I also tried if(count(site) = 0, "STE", site) but i can't get it to work.
My expected result is
+------+------------+-------+
| site | instrument | field |
+------+------------+-------+
| West | 0 | 0 |
| STE | NULL | NULL |
+------+------------+-------+
I hope you guys can help me. Thanks in advance
Both coalesce() and ifnull() work on a row basis, meaning they can replace a null value if that null value exists in a record. However, they cannot create a record that does not exist - and you do not have any records matching East (or STE).
A possible solution is to create a table that has all possible values for the site field and you can left join on this table:
SELECT
COALESCE(Table1.site, "STE") as site,
Table1.instrument,
Table1.field
FROM LookupTable lt
LEFT JOIN Table1 ON lt.site=Table1.site
WHERE lt.site IN ('East', 'West')
AND DATE(Table1.tstamp) = "2016-09-07"
ORDER BY id desc
If 'STE' isn't in table1.site then it won't come back in the results.
You could do a union instead:
SELECT
site,
instrument,
field
FROM (SELECT 'West' [Site], 0 [instrument], 0 [field]) table1
WHERE site IN ('East', 'West')
UNION
SELECT 'STE', NULL, NULL
Note that by using "STE" you're looking for the column name "STE", not the value 'STE' (single quotes)
EDIT
You need a control table to dictate which values to look for, or you have to hard code your rules. You can't look for something that's missing without first specifying the things that should be there.
Here's an option:
--Create and populate reference table "sites"
create table sites
([site] char (4))
INSERT INTO sites VALUES ('East')
INSERT INTO sites VALUES ('West')
-- Query against reference table
SELECT
ISNULL(table1.site, 'STE'),
instrument,
field
FROM (SELECT 'West' [Site], 0 [instrument], 0 [field]) table1
RIGHT JOIN sites on table1.[Site] = sites.[Site]
--or
-- Query against reference table
SELECT
ISNULL(table1.site, 'STE'),
instrument,
field
FROM sites
LEFT JOIN (SELECT 'West' [Site], 0 [instrument], 0 [field]) table1 on table1.[Site] = sites.[Site]
Let me know if you have questions on how this works.
I asked a similar question earlier today, but I've run into another issue that I need assistance with.
I have a logging system that scans a server and catalogs every user that's online at that given moment. Here is how my table looks like:
-----------------
| ab_logs |
-----------------
| id |
| scan_id |
| found_user |
-----------------
id is an autoincrementing primary key. Has no real value other than that.
scan_id is an integer that is incremented after each successful scan of all users. It so I can separate results from different scans.
found_user. Stores which user was found online during the scan.
The above will generate a table that could look like this:
id | scan_id | found_user
----------------------------
1 | 1 | Nick
2 | 2 | Nick
3 | 2 | John
4 | 3 | John
So on the first scan the system found only Nick online. On the 2nd it found both Nick and John. On the 3rd only John was still online.
My problem is that I want to get the total amount of unique users connected to the server at the time of each scan. In other words, I want the aggregate number of users that have connected at each scan. Think counter.
From the example above, the result I want from the sql is:
1
2
2
EDIT:
This is what I have tried so far, but it's wrong:
SELECT COUNT(DISTINCT(found_user)) FROM ab_logs WHERE DATE(timestamp) = CURDATE() GROUP BY scan_id
What I tried returns this:
1
2
1
The code below should give you the results you are looking for
select s.scan_id, count(*) from
(select distinct
t.scan_id
,t1.found_user
from
tblScans t
inner join tblScans t1 on t.scan_id >= t1.scan_id) s
group by
s.scan_id;
Here is sqlFiddle
It assumes the names are unique and includes current and every previous scans in the count
Try with group by clause:
SELECT scan_id, count(*)
FROM mytable
GROUP BY scan_id