Apologies if this question had been asked before (it probably did). I never used SQL before and the answers I've got only got me more confused.
I need to find out if an ID exists on different tables and get the total number from all tables.
Here is my query:
select * from public.ui1, public.ui2, public.ui3 where id = '123'
So if id 123 doesn't exist in ui1 and ui2 but does exist in ui3, I'd still like to get it. (I would obviously like to get it if it exists in the other tables)
I am currently getting an ambiguous error message as id exists in all tables but I am not sure how to construct this query in the appropriate manner. I tried join but failed miserably. Any help on how to reconstruct it and a stupid proof explanation would be highly appreciated!
EDIT: What I would finally like to find out is if id = 123 exists in any of the tables.
It's a bit unclear what the result is you expect. If you want the count then you can use a UNION ALL
select 'ui1' as source_table,
count(*) as num_rows
from public.ui1
where id = 123
union all
select 'ui2',
count(*)
from public.ui2
where id = 123
union all
select 'ui3',
count(*)
from public.ui3
where id = 123
If you only want to know if the id exists in at least one of the tables (so a true/false) result you can use:
select exists (select id from ui1 where id = 123
union all
select id from ui2 where id = 123
union all
select id from ui3 where id = 123)
What I would finally like to find out is if id = 123 exists in any of the tables.
The best way to do this is probably just using exists:
select v.id,
(exists (select 1 from public.ui1 t where t.id = v.id) or
exists (select 1 from public.ui2 t where t.id = v.id) or
exists (select 1 from public.ui3 t where t.id = v.id)
) as exists_flag
from (values (123)) v(id);
As written, this returns one row per id defined in values(), along with a flag of whether or not the id exists -- the question you are asking.
This can easily be tweaked if you want additional information, such as which tables the id exists in, or the number of times each appears.
Related
I’m trying to use a correlated subquery in my sql code and I can't wrap my head around what I'm doing wrong. A brief description about the code and what I'm trying to do:
The code consists of a big query (ALIASED AS A) which result set looks like a list of customer IDs, offer IDs and response status name ("SOLD","SELLING","IRRELEVANT","NO ANSWER" etc.) of each customer to each offer. The customers IDs and the responses in the result set are non-unique, since more than one offer can be made to each customer, and a customer can have different response for different offers.
The goal is to generate a list of distinct customer IDs and to mark each ID with 0 or 1 flag :
if the ID has AT LEAST ONE offer with status name is "SOLD" or "SELLING" the flag should be 1 otherwise 0. Since each customer has an array of different responses, what I'm trying to do is to check if "SOLD" or "SELLING" appears in this array for each customer ID, using correlated subquery in the case statement and aliasing the big underlying query named A with A1 this time:
select distinct
A.customer_ID,
case when 'SOLD' in (select distinct A1.response from A as A1
where A.customer_ID = A1.customer_ID) OR
'SELLING' in (select distinct A1.response from A as A1
where A.customer_ID = A1.customer_ID)
then 1 else 0 end as FLAG
FROM
(select …) A
What I get is a mistake alert saying there is no such object as A or A1.
Thanks in advance for the help!
You can use exists with cte :
with cte as (
<query here>
)
select c.*,
(case when exists (select 1
from cte c1
where c1.customer_ID = c.customer_ID and
c1.response in ('sold', 'selling')
)
then 1 else 0
end) as flag
from cte c;
You can also do aggregation :
select customer_id,
max(case when a.response in ('sold', 'selling') then 1 else 0 end) as flag
from < query here > a;
group by customer_id;
With statement as suggested by Yogesh is a good option. If you have any performance issues with "WITH" statement. you can create a volatile table and use columns from volatile table in your select statement .
create voltaile table as (select response from where response in ('SOLD','SELLING').
SELECT from customer table < and join voltaile table>.
The only disadvantge here is volatile tables cannot be accessed after you disconnect from session.
Using SQL Server 2012;
I am using a query to find deltas in a table.
I have an archive table that has all the records with Licenceno PK,FileID
I want to find out how many Licenceno are in a fileId but are not in previous FileID.
Code Used:
Select count(*) from table where fileid = 123 and Licenceno not in (select Licenceno from table where fileid <123)
The code works fine but the problem is some of the fileIds have the same number of records as the previous ones but take 4 hours and are still running..
Is it a table issue?
Index cant be an issue as the whole table has
a non clustered index.
It is happening generally when i am calculating deltas for the latest Licenceno.
or Query planning is the issue?
I am not able to solve this for the past 5 days.
I would rewrite your query to use an exists clause, and also add an appropriate index:
SELECT COUNT(*)(
FROM yourTable t1
WHERE
fileid = 123 AND
NOT EXISTS (SELECT 1 FROM yourTable t2
WHERE t2.Licenseno = t1.Licenseno AND t2.fileid < 123);
An index on (Licenseno, fileid) might help here:
CREATE INDEX idx ON yourTable (Licenseno, fileid);
You may also try the came composite index in the reverse order:
CREATE INDEX idx ON yourTable (fileid, Licenseno);
Why not use count(distinct)?
select count(distinct licenseno)
from table
where fileid = 123;
For this query, you want an index on (fileid, licenseno).
You are complicating the logic by thinking sequentially ("have I seen this licenseno already?"). Instead, you just want to count the distinct values.
EDIT:
For this problem, you can try two levels of aggregation:
select count(*)
from (select licenseno, min(fileid) as min_fileid
from t
where licenseno <= 123
group by licenseno
) t
where min_fileid = 123;
How good the performance is relative to other approaches dependson how selective <= 123 is.
You could also use LAG for this
SELECT COUNT(*)
FROM (SELECT fileid,
LAG(fileid) OVER (PARTITION BY Licenceno ORDER BY fileid) AS prevFileID
FROM TABLE
WHERE fileid <= 123 ) D
WHERE fileid = 123
AND prevFileID IS NULL
... or an aggregation query ...
WITH T
AS (SELECT 1 AS Flag,
FROM TABLE
WHERE fileid <= 123
GROUP BY Licenceno
HAVING MIN(fileid) = 123 )
SELECT COUNT(*)
FROM T
I have to determine how many rows are active from each Table. Then return the answers in one query AND put the results in a Table Variable.
a. Path
b. Course
c. Section
d. Event
I was able to determine the active rows with the following query:
SELECT * FROM [dbo].[ADF_Path]
WHERE PathActive is NULL
SELECT * FROM [dbo].[ADF_Course]
WHERE CourseActive = '1'OR
CourseActive = 'y'
SELECT * FROM [dbo].[ADF_Event]
WHERE EventActive = 'y'
Is it POSSIBLE to join these tables in order to arrive at the same conclusion
OR
How do I determine the active rows in 1 query?
Placing the query in a Variable Table is not a problem. I just need to know
how to formulate the query. (See Tables below)
Thank You
do you want something like?:
SELECT count(*) as cnt FROM [dbo].[ADF_Path] WHERE PathActive is NULL
union all
SELECT count(*) FROM [dbo].[ADF_Course] WHERE CourseActive = '1' OR CourseActive = 'y'
union all
SELECT count(*) FROM [dbo].[ADF_Event] WHERE EventActive = 'y'
you can also add column to distinguish between different counts, or summarize them like:
select sum(cnt) from ( <union query from above> ) as t
I am trying to update a column called Number_Of_Marks in our Results table using the results we get from our SELECT statement. Our select statement is used to count the numbers of marks per module in our results table. The SELECT statement works and the output is correct, which is
ResultID ModuleID cnt
-------------------------
111 ART3452 2
114 ART3452 2
115 CSC3039 3
112 CSC3039 3
113 CSC3039 3
The table in use is:
Results: ResultID, ModuleID, Number_Of_Marks
We need the results of cnt to be updated into our Number_Of_Marks column. This is our code below...
DECLARE #cnt INT
SELECT #cnt
SELECT C.cnt
FROM Results S
INNER JOIN (SELECT ModuleID, count(ModuleID) as cnt
FROM Results
GROUP BY ModuleID) C ON S.ModuleID = C.ModuleID
UPDATE Results
SET [Number_Of_Marks] = (#cnt)
You can do this in SQL Server using the update/join syntax:
UPDATE s
SET [Number_Of_Marks] = c.cnt
FROM Results S INNER JOIN
(SELECT ModuleID, count(ModuleID) as cnt
FROM Results
GROUP BY ModuleID
) C
ON S.ModuleID = C.ModuleID;
I assume that you want the count from the subquery, not from the uninitialized variable.
EDIT:
In general, when you change the question it is better to ask another question. Sometimes, though, the changes are really small. The revised query looks something like:
UPDATE s
SET [Number_Of_Marks] = c.cnt,
Marks = avgmarks
FROM Results S INNER JOIN
(SELECT ModuleID, count(ModuleID) as cnt, avg(marks * 1.0) as avgmarks
FROM Results
GROUP BY ModuleID
) C
ON S.ModuleID = C.ModuleID;
Note that I multiplied the marks by 1.0. This is a quick-and-dirty way to convert an integer to a numeric value. SQL Server takes averages on integers and produces an integer. Usually you want some sort of decimal or floating value.
I would like to retrieve all rows matching a set of conditions on the same column. But I would like the rows only if ALL the conditions are good, and no row if only one condition fails.
For example, taking this table:
|id|name|
---------
|1 |toto|
|2 |tata|
I would like to be able to request if "tata" && "toto" are in this table. But when asking if "tata" and "tuto" are in, I would like an empty response if one of argument is in not in the table, for example asking if "toto" && "tutu" are included in the table.
How can I do that ?
Currently, I'am doing one query per argument, which is not very efficient. I tried several solutions including a subselect or a group+having, but no one is working like I want.
thanks for your support !
cheers
This isn't the most efficient way, but this query would work.
SELECT * FROM table_name
WHERE (name = 'toto' OR name = 'tata')
AND ( SELECT COUNT(*) FROM table_name WHERE name = 'toto') > 0
AND ( SELECT COUNT(*) FROM table_name WHERE name = 'tata') > 0
This is a little vague. If the names are unique, you could count the matching rows that match a where clause:
where name='toto' or name='tata'
If the count is 2, then you know both matched. If name is not unique you could potentially select the first ID (select top 1 id ...) that matches each in a union and count those with an outer select.
Even if you had an arbitrary number of names to match, you could create a stored procedure or code in whatever top-level language you are using to build the select statement.
SELECT 1 AS found FROM hehe
WHERE 1 IN (SELECT 1 FROM hehe WHERE name='tata')
AND 1 IN (SELECT 1 FROM hehe WHERE name='toto')
If name is unique you can simplify to:
SELECT *
FROM tbl
WHERE name IN ('toto', 'tata')
AND (SELECT count(*) FROM tbl WHERE name IN ('toto', 'tata')) > 1;
If it isn't:
SELECT *
FROM tbl
WHERE name IN ('toto', 'tata')
AND EXISTS (SELECT * FROM tbl WHERE name = 'toto')
AND EXISTS (SELECT * FROM tbl WHERE name = 'tata');
Or, in PostgreSQL, MySQL and possibly others:
SELECT *
FROM tbl
WHERE name IN ('toto', 'tata')
AND (SELECT count(DISTINCT name) FROM tbl WHERE name IN ('toto', 'tata')) > 1;