I am struggling to get this answer for some reason.
I have two tables, table1 and table2 which look like this:
Table1:
ID Location Warehouse
1 London Narnia
2 Cyprus Metro
3 Norway Neck
4 Paris Triumph
Table2:
ID Area Code
1 London Narnia
2 Cyprus Metro
3 Norway Triumph
4 Paris Neck
I need to first select everything from table1 where table1.Location is in table2.Area AND table1.Warehouse is in table2.Code GIVEN THAT table1.Location is in table2.Area. I.e. I want:
ID Location Warehouse
1 London Narnia
2 Cyprus Metro
I have got to:
select
1.location
, 1.warehouse
from table1 1
where 1.location in (select area from table2)
and 1.warehouse in (select code from table2)
But this won't work because I need the second where clause to be executed based on the first where clause holding true.
I have also tried similar queries with joins to no avail.
Is there a simple way to do this?
Use exists:
select t.location, t.warehouse
from table1 t
where exists (select 1
from table2 t2
where t.location = t2.area and t.warehouse = t2.code
);
I should point out that some databases support row constructors with in. That allows you to do:
select t.location, t.warehouse
from table1 t
where(t1.location, t1.warehouse) in (select t2.area, t2.code from table2 t2);
Maybe I'm missing something, but a simple join on the two conditions would give you the result in your example:
select t1.*
from table1 t1
join table2 t2 on t1.Location = t2.Area
and t1.Warehouse = t2.Code;
Result:
| ID | Location | Warehouse |
|----|----------|-----------|
| 1 | London | Narnia |
| 2 | Cyprus | Metro |
Sample SQL Fiddle
You need to use JOIN.
I'll design the query in a while :)
EDIT:
SELECT
1.location
, 1.warehouse
FROM table1 1
JOIN table2 2 ON 1.location = 2.area AND 1.warehouse = 2.code
Related
If I have two different tables in a SQL Server 2019 database as follows:
Table1
|id | name |
+-----+--------+
| 1 | rose |
| 2 | peter |
| 3 | ann |
| 4 | rose |
| 5 | ann |
Table2
| name2 |
+--------+
|rose |
|ann |
I would like to retrieve only the last tow ids from table1 (which in this case 4 and 5) that match name2 in table2. In other words, match happens only once on the last added names in table1, furthermore, the ids (4, 5) to be inserted in table2.
How to do that using SQL?
Thank you
You can use row_number()
select name,id from
(
select *, row_number() over(partition by t.name order by id desc) as rn
from table1 t join table2 t1 on t.name=t1.name2
)A where rn=1
Your question is vague, so there could be many answers here. My first thought is that you simply want an inner join. This will fetch ONLY the data that both tables share.
SELECT Table1.*
FROM Table1
INNER JOIN Table2 on Table1.name = Table2.name2
You seem to be describing:
select . . . -- whatever columns you want
from (select top (2) t1.*
from table1 t1
order by t1.id desc
) t1 join
table2 t2
on t2.name2 = t1.name;
This doesn't seem particularly useful for the data you have provided, but it does what you describe.
EDIT:
If you want only the most recent rows that match, use row_number():
select . . . -- whatever columns you want
from (select t1.*,
row_number() over (partition by name order by id desc) as seqnum
from table1 t1
) t1 join
table2 t2
on t2.name2 = t1.name and t1.seqnum = 1;
I need to join two tables and get the most recent record only. Here is the basic form:
table1.id | table1.region | table1.important_col1
1 | NORTH AMERICA | abc
2 | CHINA | def
2 | NORTH AMERICA | hij
table2.id | table2.region | table2.transaction_date | table2.important_col2
1 | NORTH AMERICA | 2/13/2019 | xyz
1 | NORTH AMERICA | 1/13/2019 | zzz
1 | NORTH AMERICA | 12/13/2018 | xxx
desired result:
1 | NORTH AMERICA | 2/13/2019 | abc | xyz
I wanted to use this answer but it seems like I can't use it if I need to group by and then order by descending date. I will need information in multiple columns on the right hand side, but do not want duplicate rows on the left hand side.
The right hand side may have up to 100s of records per id, but I just need something that works for now. Thanks in advance.
edit: I also need to filter the right hand side on other criteria so a simple MAX(table2.transaction_date) won't work.
You can filter your table using internal window function, I used LAG for this example, but you can use ROW_NUMBER and filter several records. Using sliding windows does not change the number of records or counted as SQL aggregation, i.e. you filter using where rather than with having.
SELECT
t1.id
,t2.transaction_date
,t1.region
,t1.col1
,t2.important_col2
FROM table1 AS t1
OUTER APPLY (
SELECT
id
,transaction_date
,LAG(transaction_date,1) over (partition by id order by transaction_date desc) as prev_td
,important_col2
FROM table2
-- WHERE filter_by_col=1 -- additonal "right side" filtering
) as t2
where t1.id = t2.id
and t2.prev_td is null
Output:
1 2019-02-13 00:00:00.000 NORTH AMERICA abc xyz
I used this to test the above query:
create table table1
(id int,
region varchar(30),
col1 varchar(100));
insert into table1
values (1 ,'NORTH AMERICA' ,'abc'),
(2,'CHINA','def'),
(2,'NORTH AMERICA','hij');
create table table2
(id int,
region varchar(30),
transaction_date datetime,
important_col2 varchar(100))
insert into table2
values
(1 ,'NORTH AMERICA',convert(datetime, '02/13/19', 1),'xyz'),
(1 ,'NORTH AMERICA',convert(datetime, '01/13/19',1),'zzz'),
(1 ,'NORTH AMERICA',convert(datetime, '12/13/18',1),'xxx')
Try in this way:
select table11.id, table1.region, max(table2.transaction_date) transaction_date
from table1
inner join table2
on table1.id = table2.id
group by table1.id, table1.region
If there are more columns in table2 (other than transaction date) that you want to display as well, then aggregation alone cannot solve your question.
In MySQL 8.0 you can use window function ROW_NUMBER() to identify the most recent transaction record, as follows :
SELECT x.*
FROM (
SELECT
t1.*,
t2.*,
ROW_NUMBER() OVER(PARTITION BY t2.region ORDER BY t2.transaction_date DESC) rn
FROM table1 t1
INNER JOIN table2 t2 ON t1.region = t2.region
) x
WHERE x.rn = 1
In earlier versions of MySQL, one solution is to add a NOT EXISTS with a correlated subquery that ensures that we are joining with the most recent transaction for the current region :
SELECT t1.*, t2.*
FROM table1 t1
INNER JOIN table2 t2
ON t1.region = t2.region
AND NOT EXISTS (
SELECT 1
FROM table2
WHERE region = t2.region AND transaction_date > t2.transaction_date
)
I am wondering what should I use in SQL Server 2016 or 2017 (CTE, LOOP, JOINS, CURSOR, REPLACE, etc) to match (replace) every value in every row in temp table? What is the best solution from performance perspective?
Source Table
|id |id2|
| 1 | 2 |
| 2 | 1 |
| 1 | 1 |
| 2 | 2 |
Mapping Table
|id |newid|
| 1 | 3 |
| 2 | 4 |
Expected result
|id |id2|
| 3 | 4 |
| 4 | 3 |
| 3 | 3 |
| 4 | 4 |
You may join the second table to the first table twice:
WITH cte AS (
SELECT
t1.id AS id_old,
t1.id2 AS id2_old,
t2a.newid AS id_new,
t2b.newid AS id2_new
FROM table1 t1
LEFT JOIN table2 t2a
ON t1.id = t2a.id
LEFT JOIN table2 t2b
ON t1.id2 = t2b.id
)
UPDATE cte
SET
id_old = id_new,
id2_old = id2_new;
Demo
Not sure if you want just a select here, or maybe an update, or an insert into another table. In any case, the core logic I gave above should work for all these cases.
You'd need to apply joins on update query. Something like this:
Update tblA set column1 = 'something', column2 = 'something'
from actualName tblA
inner join MappingTable tblB
on tblA.ID = tblB.ID
this query will compare eachrow with ids and if matched then it will update/replace the value of the column as you desire. :)
Do the self join only
SELECT t1.id2 as id, t2.id2
FROM table1 t
INNER JOIN table2 t1 on t1.id = t.id
INNER JOIN table2 t2 on t2.id = t.id2
This may have best performance from solutions posted here if you have indexes set appropriately:
select (select [newid] from MappingTable where id = [ST].[id]) [id],
(select [newid] from MappingTable where id = [ST].[id2]) [id2]
from SourecTable [ST]
I am trying to join two tables one is a unique feature the seconds is readings taken on several dates that relate to the unique features. I want all of the records in the first table plus the most recent reading. I was able to get the results I was looking for before adding the shape field. By using the code
SELECT
Table1.Name, Table1.ID, Table1.Shape,
Max(Table2.DATE) as Date
FROM
Table1
LEFT OUTER JOIN
Table2 ON Table1.ID = table2.ID
GROUP BY
Table1.Name, Table1.ID, Table1.Shape
The shape field is a geometry type and I get the error
'The type "Geometry" is not comparable. It can not be use in the Group By Clause'
So I need to go about it a different way, but not sure how.
Below is a sample of the two tables and the desired results.
Table1
Name| ID |Shape
AA1 | 1 | X
BA2 | 2 | Y
CA1 | 3 | Z
CA2 | 4 | Q
Table2
ID | Date
1 | 5/27/2013
1 | 6/27/2014
2 | 5/27/2013
2 | 6/27/2014
3 | 5/27/2013
3 | 6/27/2014
My Desired Result is
Name| ID |Shape |Date
AA1 | 1 | X | 6/27/2014
BA2 | 2 | Y | 6/27/2014
CA1 | 3 | Z | 6/27/2014
CA2 | 4 | Q | Null
You can do the aggregation on Table2 in a CTE, finding the MAX(DATE) for each ID, and then join that result to Table1:
WITH AggregatedTable2(ID, MaxDate) AS
(
SELECT
ID, MAX(DATE)
FROM
Table2
GROUP BY
ID
)
SELECT
t1.ID, t1.Name, t1.Shape, t2.MaxDate
FROM
Table1 t1
LEFT JOIN
AggregatedTable2 t2 ON t1.ID = t2.ID
Try casting geometry as a varchar.
Select Table1.Name, Table1.ID, cast(Table1.Shape as varchar(1)) AS Shape, Max(Table2.DATE) as Date
FROM Table1 LEFT OUTER JOIN
Table2 ON Table1.ID = table2.ID
Group By Table1.Name, Table1.ID, cast(Table1.Shape as varchar(1))
Try this:
SELECT t1.Name
, t1.ID
, t1.Shape
, MAX(t2.Date) As Date
FROM Table1 AS t1
LEFT JOIN Table2 AS t2
ON t2.ID = t1.ID
GROUP
BY t1.Name
, t1.ID
, t1.Shape
I'm wondering if anybody can help me solve this question I got at a job interview. Let's say I have two tables like:
table1 table2
------------ -------------
id | name id | name
------------ -------------
1 | alpha 1 | alpha
3 | charlie 3 | charlie
4 | delta 5 | echo
8 | hotel 7 | golf
9 | india
The question was to write a SQL query that would return all the rows that are in either table1 or table2 but not both, i.e.:
result
------------
id | name
------------
4 | delta
5 | echo
7 | golf
8 | hotel
9 | india
I thought I could do something like a full outer join:
SELECT table1.*, table2.*
FROM table1 FULL OUTER JOIN table2
ON table1.id=table2.id
WHERE table1.id IS NULL or table2.id IS NULL
but that gives me a syntax error on SQL Fiddle (I don't think it supports the FULL OUTER JOIN syntax). Other than that, I can't even figure out a way to just concatenate the rows of the two tables, let alone filtering out rows that appear in both. Can somebody enlighten me and tell me how to do this? Thanks.
Well, you could use UNION instead of OUTER JOIN.
SELECT * FROM table1 t1
LEFT JOIN table2 t2 ON t1.id = t2.id
UNION
SELECT * FROM table1 t1
RIGHT JOIN table2 t2 ON t1.id = t2.id
Here's a little trick I know: not equals is the same as XOR, so you could have your WHERE clause something like this:
WHERE ( table1.id IS NULL ) != ( table2.id IS NULL )
select id,name--,COUNT(*)
from(
select id,name from table1
union all
select id,name from table2
) x
group by id,name
having COUNT(*)=1
I'm sure there are lots of solutions, but the first thing that comes to mind for me is to union all the two tables, then group by name, filter with a having clause on the count.
(
SELECT * FROM TABLE1
EXCEPT
SELECT * FROM TABLE2
)
UNION ALL
(
SELECT * FROM TABLE2
EXCEPT
SELECT * FROM TABLE1
)
This should work on most database servers
SELECT id, name
FROM table1
WHERE NOT EXISTS(SELECT NULL FROM table2 WHERE table1.id = table2.id AND table1.name = table2.name)
UNION ALL
SELECT id, name
FROM table2
WHERE NOT EXISTS(SELECT NULL FROM table1 WHERE table1.id = table2.id AND table1.name = table2.name)