I need to select from all users that are not present in a set of other sub queries:
SELECT user_id
FROM (<userSubQuery1>)
WHERE
user_id NOT IN (<badUserSubQueryA>) AND
user_id NOT IN (<badUserSubQueryB>) AND
user_id NOT IN (<badUserSubQueryC>)
Only I need to do the NOT IN filters in many different queries where the userSubQuery and the badUserSubQueries may be different. E.g.:
SELECT user_id
FROM (<userSubQuery2>)
WHERE
user_id NOT IN (<badUserSubQueryB>) AND
user_id NOT IN (<badUserSubQueryC>) AND
user_id NOT IN (<badUserSubQueryD>)
All the sub queries, both the ones I'm selecting from and the once used in the NOT IN are complex so I don't want to duplicate the code for the NOT IN sub queries which are often the same (badUserSubQueryB and badUserSubQueryC in my example).
I could achieve this with dynamic sql but I'd rather not if I can avoid it. Is it possible?
How about storing all the bad user IDs in an indexed temporary table from which you can filter?
How about creating a view for each complex subquery that you want to reuse?
I would have a crack at it like this:
Try to think of this in reverse logic like this
SELECT user_id
FROM (<userSubQuery1>)
MINUS
(
SELECT useri_id
FROM <badUserSubQueryB>
UNION
SELECT useri_id
FROM <badUserSubQueryC>
UNION
SELECT useri_id
FROM <badUserSubQueryD>
)
Let me know how it goes
Cheers ,
Alex
Related
I have built cohorts of accounts based on date of first usage of our service. I need to use these cohorts in a handful of different queries, but don't want to have to create the queries in each of these downstream queries. Reason: Getting the data the first time took more than 60 minutes, so i don't want to pay that tax for all the other queries.
I know that I could do a statement like the below:
WHERE ACCOUNT_ID IN ('1234567','7891011','1213141'...)
But, I'm wondering if there is a way to create a temporary table that I prepopulate with my data, something like
WITH MAY_COHORT AS ( SELECT ACCOUNT_ID Account_ID, '1234567' Account_ID, '7891011' Account_ID, '1213141' )
I know that the above won't work, but would appreciate any advice or counsel here.
thanks.
Unless I am missing something, you're already on the right track, just an adjustment to your CTE should work:
WITH MAY_COHORT AS ( SELECT Account_ID from TableName WHERE ACCOUNT_ID IN ('1234567','7891011','1213141'...) )
This should give you the May_Cohort table to use for subsequent queries.
You can also use a sub-select for your Ids (no WITH MY_COHORT):
WHERE ACCOUNT_ID IN (
SELECT Account_ID
from TableName "Where ... your condition to build your cohort ..." )
Given the below table as a SQL Result:
I want to use the above generated table and produce a table which clubs the given information into:
I have multiple areaName and multiple functionNames and multiple users. Please let me know if this is possible and how?
I have tried couple of things but I am just drained out now and need a direction. Any help is appreciated.
Even if you can provide a pseudo code, I can try and make use of it. Start from the SQL result as a given table.
Use correlated sub-queries to achieve the desired result. I've provided an example below. Test it for the first summary column, and then add in your other summary columns if it does. Hopefully this makes sense, and helps. Alternatively you could use a CTE (common table expression) to achieve similar results.
SELECT a.areaName, a.functionName
, (SELECT count(DISTINCT b.UserKey)
from AREAS b
where a.areaName = b.areaName
and a.functionName = b.functionName
and b.[1-add] = 1) as UsersinAdd
-- Lather/rinse/repeat for other summary columns
FROM AREAS a
group by a.areaName, a.functionName
Your problem stems from the de-normalised structure of your table. Columns [1-add],...,[8-correction] should be values in a column, not columns. This leads to more complex queries, as you have discovered.
The unpivot command allows you to correct this mistake.
select areaname, functionname, rights, count(distinct userkey)
from
(
select * from yourtable
unpivot (permission for rights in ([1-add], [2-update/display],[4-update/display all] , [8-correction] )) u
) v
group by areaname, functionname, rights
I want to get the rownumbers in sql select statement but it shouldn't be DB specific query like I cant use rownum of oracle.Please let me know how can i achieve this.
I have table structure as follows pid,emplid,desc as colums and pid and emplid combination will be used as primary key. So suggest the query in this use case.
Thanks,
Shyam
The row_number() function is supported on a lot of the major RDBMS but I don't believe it's in MySQL so it really depends how agnostic you want it to be. Might be best to move it out of the database layer if you want it truly agnostic.
EDIT: valex's method of calculating rownum is probably a better option than moving it out of DB
To do it you table has to have an unique Id- like field - anything to distinguish one row from another. If it is then:
select t1.*,
(select count(id) from t as t2 where t2.id<=t1.id) as row_number
from t as t1 order by Id
UPD: if you have 2 columns to make an order then it will look like:
select t1.*,
(select count(id) from t as t2 where t2.id1<=t1.id1 and t2.id2<=t1.id2)
as row_number
from t as t1 order by Id1,id2
I have a table with 3 columns:
userid mac_address count
The entries for one user could look like this:
57193 001122334455 42
57193 000C6ED211E6 15
57193 FFFFFFFFFFFF 2
I want to create a view that displays only those MAC's that are considered "commonly used" for this user. For example, I want to filter out the MAC's that are used <10% compared to the most used MAC-address for that user. Furthermore I want 1 row per user. This could easily be achieved with a GROUP BY, HAVING & GROUP_CONCAT:
SELECT userid, GROUP_CONCAT(mac_address SEPARATOR ',') AS macs, count
FROM mactable
GROUP BY userid
HAVING count*10 >= MAX(count)
And indeed, the result is as follows:
57193 001122334455,000C6ED211E6 42
However I really don't want the count-column in my view. But if I take it out of the SELECT statement, I get the following error:
#1054 - Unknown column 'count' in 'having clause'
Is there any way I can perform this operation without being forced to have a nasty count-column in my view? I know I can probably do it using inner queries, but I would like to avoid doing that for performance reasons.
Your help is very much appreciated!
As HAVING explicitly refers to the column names in the select list, it is not possible what you want.
However, you can use your select as a subselect to a select that returns only the rows you want to have.
SELECT a.userid, a.macs
FROM
(
SELECT userid, GROUP_CONCAT(mac_address SEPARATOR ',') AS macs, count
FROM mactable
GROUP BY userid
HAVING count*10 >= MAX(count)
) as a
UPDATE:
Because of a limitation of MySQL this is not possible, although it works in other DBMS like Oracle.
One solution would be to create a view for the subquery. Another solution seems cleaner:
CREATE VIEW YOUR_VIEW (userid, macs) AS
SELECT userid, GROUP_CONCAT(mac_address SEPARATOR ',') AS macs, count
FROM mactable
GROUP BY userid
HAVING count*10 >= MAX(count)
This will declare the view as returning only the columns userid and macs although the underlying SELECT statement returns more columns than those two.
Although I am not sure, whether the non-DBMS MySQL supports this or not...
For examples I don't know how many rows in each table are and I try to do like this:
SELECT * FROM members
UNION
SELECT * FROM inventory
What can I put to the second SELECT instead of * to remove this error without adding NULL's?
Put the columns names explicitly rather than *, and make sure the number of columns and data types match for the same column in each select.
Update:
I really don't think you want to be UNIONing those tables, based on the tables names. They don't seem to contain related data. If you post your schema and describe what you are trying to achieve it is likely we can provide better help.
you could do
SELECT *
from members
UNION
SELECT inventory.*, 'dummy1' AS membersCol1, 'dummy2' AS membersCol2
from inventory;
Where membersCol1, membersCol12, etc... are the names of columns from members that are not in inventory. That way both queries in the union will have the same columns (Assuming that all the columns in inventory are the same as in members which seems very strange to me... but hey, it's your schema).
UPDATE:
As HLGEM pointed out, this will only work if inventory has columns with the same names as members, and in the same order. Naming all the columns explicitly is the best idea, but since I don't know the names I can't exactly do that. If I did, it might look something like this:
SELECT id, name, member_role, member_type
from members
UNION
SELECT id, name, '(dummy for union)' AS member_role, '(dummy for union)' AS member_type
from inventory;
I don't like using NULL for dummy values because then it's not always clear which part of the union a record came from - using 'dummy' makes it clear that the record is from the part of the union that didn't have that record (though sometimes this might not matter). The very idea of unioning these two tables seems very strange to me because I very much doubt they'd have more than 1 or 2 columns with the same name, but you asked the question in such a way that I imagine in your scenario this somehow makes sense.
Are you sure you don't want a join instead? It is unlikely that UNOIN will give you what you want given the table names.
Try this
(SELECT * FROM members) ;
(SELECT * FROM inventory);
Just add semicolons after both the select statements and don't use union or anything else. This solved my error.
I don't know how many rows in each table
Are you sure this isn't what you want?
SELECT 'members' AS TableName, Count(*) AS Cnt FROM members
UNION ALL
SELECT 'inventory', Count(*) FROM inventory
Each SELECT statement within the MySQL UNION ALL operator must have the same number of fields in the result sets with similar data types
Visit https://www.techonthenet.com/mysql/union_all.php