Is it possible to insert from a list of values from within in mysql?
INSERT INTO changes(uid,typ)
SELECT owner,(SELECT * FROM(20,30,40)) lst
FROM info
To put it another way, can you make a list of values act like the result a sub query?
Actually, what you're trying to do is sintactically and semantically incorrect :) You're trying to return 3 rows from a select and put them into the outer select which just accepts one single value (1 column x 1 row).
Besides there is no way for MySQL to know to which user correponds each number, right? Then, if you had a way to link a user in the inner select to the outer select then you would have two tables and you would join them.
Now if you are actually looking to join each owner to each of the numbers you're looking for a cartesian product. And you can do it like this:
select owner from info, (select 20 union select 30 union select 40) t2
This way, we're creating a dummy table with 3 records and each of those records we're linking them to the owner, this would result in:
owner1 | 20
owner1 | 30
owner1 | 40
owner2 | 20
owner2 | 30
owner2 | 40
owner3 | 20
And so on. Is it clear?
Related
I have table:
id | parent | regno | person
1 | 0 | 12 | 5
2 | 1 | 12 | 15
3 | 0 | 13 | 5
4 | 0 | 14 | 6
I have MySQL query...
SELECT *
FROM table
WHERE person='5';
...that returns rows 1 and 3.
In this table row 1 and 2 are related (same regno).
How can i build this query to include related rows?
Basically when searching for person 5 i need MySQL query to return following:
id | parent | regno | person
1 | 0 | 12 | 5
2 | 1 | 12 | 15
3 | 0 | 13 | 5
Parent column has id of column it is related to, but it can be positive and negative integer. All related rows always have same regno.
Thank you.
You want all people who have a regno that is the same as the regno of anyone who is person 5:
--this main query finds all people with the regno from the subquery
SELECT *
FROM table
WHERE regno IN
( --this subquery finds the list of regno
SELECT regno
FROM table
WHERE person = '5'
)
There are other ways to write this; i'm not a fan of IN, and personally would write it like this:
SELECT t.*
FROM table t
INNER JOIN
(
SELECT DISTINCT regno
FROM table
WHERE person = '5'
) u
WHERE t.regno = u.regno
But it's harder to understand, and it's quite likely that these queries would end up being executed identically internally anyway. In this form the DISTINCT is required to make the regno from the subquery unique. If it were not, joined rows would end up duplicated. Why do I prefer it over IN? In some database systems IN's implementation can be very naive and low performing. "Never use IN to create a list longer then you would write by hand" is an old mantra I tend to stick to. This join pattern is also more flexible, can work with multiple values. Not every database supports Oracle-esque where x,y in ((1,3),(3,4)) value multiples
As an aside (and partly in response to the first comment on this answer) it would be more typical and more useful/usual to have the database prepare a set of rows that had parent and child data on the same line
It would look more like this:
SELECT *
FROM
table c
LEFT OUTER JOIN
table p
ON c.regno = p.regno AND p.parent = 1
WHERE c.person = '5' AND c.parent=0
This is assuming your "parent" column is 0 1 indicating true false.. you seem to have made a comment that parent is the id of the relative (not sure if it's parent-of or parent-is)
For a table where there is an id, and parentid column, and the parentid is set to a value when the row is a child of that other id;
id, parentid, name
1, null, Daddy
2, 1, Little Jonny
3, 1, Little Sarah
That looks like:
SELECT *
FROM
table c
INNER JOIN
table p
ON c.parentid = p.id
WHERE p.parentid ID NULL
Rows can have only one parent. A NULL in the parent id defines the row as being a parent, otherwise it's a child. You could turn this logic on its head if you wanted, call the column isparentof and have all child rows with null in the isparentof, and anyone who is a parent of a child, out the child id in isparentof. This then limits you to one child per multiple parents (single child families).. the query to pull them out is broadly the same
You can get all the id values for the person = '5' in a Derived Table.
Now, join back to the main table, matching either the absolute of parent (to get the child row(s)) or the id (to get the parent id row itself).
Based on discussion in comments, Try:
SELECT t.*
FROM your_table AS t
JOIN
(
SELECT id AS parent_id
FROM your_table
WHERE person = '5'
) AS dt
ON dt.parent_id = ABS(t.parent) OR
dt.parent_id = t.id
It is hard to comprehend though, why would you put negative values in parent!
I'm having 2 tables. Table A contains a list of people who booked for an event, table B has a list of people the booker from table A brings with him/her. Both tables have many colums with unique data that I need to do certain calculations on in PHP , and as of now I do so by doing queries on the tables with a recursive PHP function to resolve it. I want to simplify the PHP and reduce the amount of queries that come from this recursive function by doing better MYSQL queries but I'm kind of stuck.
Because the table has way to many columns I will give an Excerpt of table A instead:
booking_id | A_customer | A_insurance
1 | 134 | 4
Excerpt of table B:
id | booking_id | B_insurance
1 | 1 | 0
2 | 1 | 1
3 | 1 | 1
4 | 1 | 3
The booking_id in table A is unique and set to auto increment, the booking_id in table b can occur many times (depending on how many guests the client from table A brings with him). Lets say I want to know every selected insurance from customer 134 and his guests, then I want the output like this:
booking_id | insurance
1 | 4
1 | 0
1 | 1
1 | 1
1 | 3
I have tried a couple of joins and this is the closest I've came yet, unfortunately this fails to show the row from A and only shows the matching rows in B.
SELECT a.booking_id,a.A_customer,a.A_insurance,b.booking_id,b.insurance FROM b INNER JOIN a ON (b.booking_id = a.booking_id) WHERE a.booking_id = 134
Can someone point me into the right direction ?
Please note: I have altered the table and column names for stackoverflow so it's easy for you guys to read, so it's possible that there is a typo that would break the query in it right now.
I think you need a union all for this:
select a.booking_id, a.insurance
from a
where a.a_customer = 134
union all
select b.booking_id, b.insurance
from a join
b
on a.booking_id = b.booking_id
where a.a_customer = 134;
The simplest way I can think of to achieve this is to use a UNION:
SELECT booking_id, A_insurance insurance
FROM A
WHERE booking_id = 134
UNION
SELECT booking_id, B_insurance insurance
FROM B
WHERE booking_id = 134
As my understanging of your isso is right, that should give you the result you need:
SELECT a.booking_id,a.insurance FROM a WHERE a.booking_id = 134
union
SELECT a.booking_id,b.insurance FROM b INNER JOIN a ON (b.booking_id = a.booking_id) WHERE a.booking_id = 134
I need to count the number of duplicate emails in a mysql database, but without counting the first one (considered the original). In this table, the query result should be the single value "3" (2 duplicate x#q.com plus 1 duplicate f#q.com).
TABLE
ID | Name | Email
1 | Mike | x#q.com
2 | Peter | p#q.com
3 | Mike | x#q.com
4 | Mike | x#q.com
5 | Frank | f#q.com
6 | Jim | f#q.com
My current query produces not one number, but multiple rows, one per email address regardless of how many duplicates of this email are in the table:
SELECT value, count(lds1.leadid) FROM leads_form_element lds1 LEFT JOIN leads lds2 ON lds1.leadID = lds2.leadID
WHERE lds2.typesID = "31" AND lds1.formElementID = '97'
GROUP BY lds1.value HAVING ( COUNT(lds1.value) > 1 )
It's not one query so I'm not sure if it would work in your case, but you could do one query to select the total number of rows, a second query to select distinct email addresses, and subtract the two. This would give you the total number of duplicates...
select count(*) from someTable;
select count(distinct Email) from someTable;
In fact, I don't know if this will work, but you could try doing it all in one query:
select (count(*)-(count(distinct Email))) from someTable
Like I said, untested, but let me know if it works for you.
Try doing a group by in a sub query and then summing up. Something like:
select sum(tot)
from
(
select email, count(1)-1 as tot
from table
group by email
having count(1) > 1
)
I have my table: call it tblA THis table has three rows, id, sub-id, and visibility
sub-id is the primary key (it defines taxonomies for id). I'm trying to build a query that selects every id that appears less than three times.
here is an example query/result
select * from tbla where id = 188002;
+--------+--------+-------------+
| sub-id | id | visibility |
+--------+--------+-------------+
| 284922 | 188002 | 2 |
| 284923 | 188002 | 2 |
| 284924 | 188002 | 0 |
+--------+--------+-------------+
From what i've seen here and here it looks like I need to join the table on...itself. I dont really understand what that accomplishes.
If anyone has insight into this, it is appreciated. I will continue to research it and update this topic with any additional information I come across.
Thanks
SELECT id
FROM tbla
GROUP BY id
HAVING COUNT(*) < 3
If you want to select all columns from the table, you will have to use #Joe's query in a sub-select:
SELECT * FROM tbla a
WHERE a.id IN (SELECT DISTINCT b.id
FROM tbla b
GROUP BY b.id
HAVING COUNT(*) < 3)
This query first selects all id's that have fewer than 3 duplicates.
The distinct eliminates duplicates, the query works the same without, but slightly slower.
Next it selects all rows that have an id that meets the criteria in the sub-select i.e. that have fewer than 3 duplicate id's.
The reason that you cannot do this in one go is that the group by heaps all rows with the same id together into one super-row (for want of a better metafor) .
You cannot separate out the columns that are not in the group by clause.
The outer select solves this.
For simplicity, I will give a quick example of what i am trying to achieve:
Table 1 - Members
ID | Name
--------------------
1 | John
2 | Mike
3 | Sam
Table 1 - Member_Selections
ID | planID
--------------------
1 | 1
1 | 2
1 | 1
2 | 2
2 | 3
3 | 2
3 | 1
Table 3 - Selection_Details
planID | Cost
--------------------
1 | 5
2 | 10
3 | 12
When i run my query, I want to return the sum of the all member selections grouped by member. The issue I face however (e.g. table 2 data) is that some members may have duplicate information within the system by mistake. While we do our best to filter this data up front, sometimes it slips through the cracks so when I make the necessary calls to the system to pull information, I also want to filter this data.
the results SHOULD show:
Results Table
ID | Name | Total_Cost
-----------------------------
1 | John | 15
2 | Mike | 22
3 | Sam | 15
but instead have John as $20 because he has plan ID #1 inserted twice by mistake.
My query is currently:
SELECT
sq.ID, sq.name, SUM(sq.premium) AS total_cost
FROM
(
SELECT
m.id, m.name, g.premium
FROM members m
INNER JOIN member_selections s USING(ID)
INNER JOIN selection_details g USING(planid)
) sq group by sq.agent
Adding DISTINCT s.planID filters the results incorrectly as it will only show a single PlanID 1 sold (even though members 1 and 3 bought it).
Any help is appreciated.
EDIT
There is also another table I forgot to mention which is the agent table (the agent who sold the plans to members).
the final group by statement groups ALL items sold by the agent ID (which turns the final results into a single row).
Perhaps the simplest solution is to put a unique composite key on the member_selections table:
alter table member_selections add unique key ms_key (ID, planID);
which would prevent any records from being added where the unique combo of ID/planID already exist elsewhere in the table. That'd allow only a single (1,1)
comment followup:
just saw your comment about the 'alter ignore...'. That's work fine, but you'd still be left with the bad duplicates in the table. I'd suggest doing the unique key, then manually cleaning up the table. The query I put in the comments should find all the duplicates for you, which you can then weed out by hand. once the table's clean, there'll be no need for the duplicate-handling version of the query.
Use UNIQUE keys to prevent accidental duplicate entries. This will eliminate the problem at the source, instead of when it starts to show symptoms. It also makes later queries easier, because you can count on having a consistent database.
What about:
SELECT
sq.ID, sq.name, SUM(sq.premium) AS total_cost
FROM
(
SELECT
m.id, m.name, g.premium
FROM members m
INNER JOIN
(select distinct ID, PlanID from member_selections) s
USING(ID)
INNER JOIN selection_details g USING(planid)
) sq group by sq.agent
By the way, is there a reason you don't have a primary key on member_selections that will prevent these duplicates from happening in the first place?
You can add a group by clause into the inner query, which groups by all three columns, basically returning only unique rows. (I also changed 'premium' to 'cost' to match your example tables, and dropped the agent part)
SELECT
sq.ID,
sq.name,
SUM(sq.Cost) AS total_cost
FROM
(
SELECT
m.id,
m.name,
g.Cost
FROM
members m
INNER JOIN member_selections s USING(ID)
INNER JOIN selection_details g USING(planid)
GROUP BY
m.ID,
m.NAME,
g.Cost
) sq
group by
sq.ID,
sq.NAME