Sorry I missed and deleted earlier question on accident again.
I have a situation, I am trying to select distinct values from table 1 that are new and store them in table 2. The problem is that table has duplicates on column "name" but it does have a key column "id", but the different ids of course map to the same name.
My idea on the query would be
INSERT INTO TABLE2
(NAME, UniqueID)
SELECT DISTINCT TABLE1.NAME, TABLE1.ID
FROM TABLE1
LEFT JOIN TABLE2 ON TABLE1.ID=TABLE2.UniqueID
WHERE TABLE2.NAME IS NULL
Need help on getting the query to return my desired results, right now it still produces duplicates in table2 (on name column), which I don't want. I would want it to only append new records even if I run the query multiple times. For example if two new records were added into table1 but one has the name already in table 2, then the query would only add 1 new record to table2
just a note: I am using ms access, so it has strict syntax on single queries
EDIT:
Folliwing input I had came with this query
INSERT INTO TABLE2
(NAME, UniqueID)
SELECT TABLE1.NAME, Min(TABLE1.ID)
FROM TABLE1
LEFT JOIN TABLE2 ON TABLE1.NAME=TABLE2.NAME
WHERE TABLE2.UniqueID IS NULL
Group By TABLE1.NAME;
but these actually had to be separated to two separate wueries in access to run without a reserver error flag but now I ran into additional problem. When I run the two separate queries, it works fine the first time, but when I run it twice trying to test to see if any new records have been added to table 1, it then appends 1 record when no new records are in table 1, so it appends a blank name value and a duplicate unique id, and continually does that same process everytime I run it.
Since you're pulling both Name and ID, the distinct keyword will only pull distinct combinations of those. Two records with the same Name and different ID's is still valid.
In the case of two Names with different ID's, which would you like to be inserted?...
insert into table2 (Name, UniqueID)
select t1.Name, MIN(t1.ID)
from table1 t1
left join table2 t2 on t1.ID = t2.UniqueID
where t2.Name is null
group by t1.Name
in response to comments, I realize the Name field is what should be joined on, to prevent dupes that already exist.
insert into table2 (Name, UniqueID)
select t1.Name, MIN(t1.ID)
from table1 t1
left join table2 t2 on t1.Name = t2.Name
where t2.UniqueID is null
group by t1.Name
INSERT INTO TABLE2 (UniqueID, NAME)
SELECT min(t1.ID) as UniqueID, t1.NAME
FROM TABLE1 t1
LEFT JOIN TABLE2 t2 ON t1.ID=t2.UniqueID
WHERE t2.NAME IS NULL
group by t1.NAME
Related
I have two tables.
Table 1
Id
UpdateId
Name
Table 2
Table1ID
UpdateID
Address
Each time user update, system will insert record to table1. But for table2, system only insert record when there is update in address.
Sample data
Table 1
1,1,name1
1,2,name1
1,3,name1update
1,4,name1update
1,5,name1
1,6,name2
Table 2
1,1,address
1,4,addressupdate
I want to get the result as following
1,1,name1,address
1,2,name1,address
1,3,name1update,address
1,4,name1update,addressupdate
1,5,name1,addressupdate
1,6,name2,addressupdate
How to make use of join condition to achieve as above?
You can use a correlated subquery. Here is standard syntax, but it can be easily adapted to any database:
select t1.*,
(select t2.addressid
from table2 t2
where t2.table1id = t1.id and
t2.updateid <= t1.updateid
order by t2.updateid desc
fetch first 1 row only
) as addressid
from table1 t1;
you can use left join when you want to take all columns from left table t1 even though it doesn't match with the other table with column updateid on t2 table.
select t1.id,t1.updateid,t1.name,t2.address from table1 t1
left join table2 t2
on t2.updateid= t1.updateid
you can read more about joins here
I have a query that I'm trying to rework that has over 1,000 columns when I select * FROM several tables. I want to know if there is a way in SQL to tag the column alias with the table alias so i can know from which table the columns are from. It looks like the following:
SELECT *
FROM table1 t1
join table2 t2
join table3 t3
join table4 t4
Current column output:
id, id, id, id, name, name, name, name, order, order, order, order
Desired Column output:
t1.id, t1.name, t1.order, t2.id, t2.name, t2.order,t3.id, t3.name, t3.order, t4.id, t4.name, t4.order
this is a very simple example but you can imagine trying to fish out the column you need of a sea of 1,000 columns trying to figure out what table it came from! Any ideas??
I'm not aware of a way to prefix each column with the column alias. However I do know how you could easily break the columns into groups that would allow you to figure out which table each column comes from.
SELECT 'T1' as [Table1]
, t1.*
, 'T2' as [Table2]
, t2.*
, 'T3' as [Table3]
, t3.*
, t4.* as [Table4]
, t4.*
, 'T5' as [Table5]
, t5.*
FROM table1 t1
join table2 t2
join table3 t3
join table4 t4
This would break out the columns into groups by table and it would break a little bookmark before and after each group to help you understand where they're coming.
I know not exactly what you asked for but I believe it would help you a lot in figuring out what's from what tables.
Your other option is as others have said and specifiying the prefix on every column which it sounds like you don't want to do. However it can be a lot quicker to do this if you drag the columns from the Object Explorer - and use ALT-SHIFT to add the prefix to each column.
Here's an article about copying columns from object explorer - https://www.qumio.com/Blog/Lists/Posts/Post.aspx?ID=56
Her's an article about adjusting code using ALT+SHIFT - https://blogs.msdn.microsoft.com/sql_pfe_blog/2017/04/11/quick-tip-shiftalt-for-multiple-line-edits/
The first method would take less than a method, the 2nd method I could see taking less than 10 minutes even for 1,000 columns.
You have to assign non-default column aliases manually:
select t1.id as t1_id, t1.name as t1_name, t1.order as t1_order,
t2.id as t2_id, t2.name as t2_name, t2.order as t2_order,
. . .
You might find that a spreadsheet or query can help, if you have a lot of columns.
Some products may have exceptions, but generally no, you can't do that. You either have to use wildcards (SELECT *) or specify the columns you wish returned by full and complete name.
If you specify columns, you can "alias" them, set the column name to something other than the source name. For example (psuedo-code, leaving out the "ON" clause):
SELECT
T1.Id as T1_Id
,T2.Id as T2_Id
from table1 T1
join table2 T2
Note that you can combine table aliases with wildcards. For example:
SELECT
T2.*
from table1 T1
join table2 T2
join table3 T3
join table4 T5
will return all the columns from table2, and only from table2. This might help in revising your query by getting a list of the available columns in each table.
I want to get a value from an IN subquery with two columns, without needing to do two queries.
Sample:
SELECT * FROM table1 WHERE id IN(SELECT id, flags FROM table2);
Now I want to get flags directly. Is it possible, and if yes, how?
Any help is appreciated :)
It sounds like you are trying to achieve one of two things:
1) Select every field of records in table1 (and the associated table 2 flag) where the record's id is also found in the id column of table2. If that is the case, then yes, a join will accomplish what you want:
SELECT t1.*,
t2.flags
FROM table1 t1
JOIN table2 t2
ON t1.id = t2.id;
Note that JOIN is used here (rather than other types of joins such as LEFT JOIN) because JOIN will return only table1 records with a match in table2.id. LEFT JOIN, on the other hand, would return every table1 record, and table1 ids without a match in table2 would simply have null in the flags column of your returned table.
2) Select every field of records in table1 where the record's id is also found in either the id column of table2 or the flags column of table2. If that is the case, there are a few ways you could get the desired result, but achieving this using a subquery similar to the question
SELECT *
FROM table1
WHERE id IN (SELECT id FROM table2 UNION DISTINCT SELECT flags FROM table2)
You do this using join:
SELECT t1.*, t2.flags
FROM table1 t1 JOIN
table2 t2
ON t1.id = t2.id;
I am trying to write an SQL query that will return Table1, which has 10 columns. This table consists of a primary key id, 4 foreign key Id columns, and 5 other columns that I want to return but not change. The goal is to do a join to replace the foreign key Ids with their descriptions that are held in other tables.
Here is one attempt with the first FK Id:
Select * from Table1 t1
left join Table2 t2
on t1.BranchId = t2.BranchId;
This left join returns the description from table2, but does not replace it.
Here is another with the first FK Id:
Select t2.BranchName from Table1 t1
left join Table2 t2
on t1.BranchId = t2.BranchId;
This returns the name I want, but does not return table1 fully.
For the sake of an example you could pretend that OtherName3, OtherName4, OtherName5 are in tables Table3, Table4, Table5, respectively.
This may seem trivial for experienced SQL devs, but I am having a hard time figuring out the syntax.
Thanks!
I'm not sure what you mean by replace it.
I think you just need to list out all the columns you want:
Select t1.col1, t1.col2, t1.col3, . . .,
t2.name
from Table1 t1 left join
Table2 t2
on t1.BranchId = t2.BranchId;
I don't know what you mean by 'replace' but you just need to qualify what columns from which table you want. That goes for all tables you are joined to, especially if they have the same column name in multiple tables. I put junk columns in since I don't know your tables but you should get the general idea.
Select t2.BranchName, t1.BranchId, t1.Name, t1.Amount, t2.BranchLocation from Table1 t1
left join Table2 t2
on t1.BranchId = t2.BranchId;
I think this is what you are looking for:
select t1.*, t2.BranchName from Table1 t1
left join Table2 t2
on t1.BranchId = t2.BranchId;
Return Table1 fully (all columns) and only the description (BranchName) from Table2.
If using SQL Server, see all syntax options for the SELECT clause here:
https://msdn.microsoft.com/en-us/library/ms176104.aspx
I have two tables where each one contains columns with numbers. I need to compare columns in both tables and extract the number that does exist in first table, and does not exist in second one. I don't need unique value.
I wrote this query:
SELECT Table1.Numbers, Table1.Name
FROM Table1, Table2
WHERE Table1.Numbers != Table2.numbers
Since I am working on several million records can someone recommend more efficient query which would provide me with identical results?
I would use NOT EXISTS:
SELECT Table1.Numbers, Table1.Name
FROM Table1
WHERE NOT EXISTS(
SELECT 1 FROM Table2
WHERE Table1.Numbers=Table2.Numbers
)
Other approaches:
Should I use NOT IN, OUTER APPLY, LEFT OUTER JOIN, EXCEPT, or NOT EXISTS?
You can do this easily by checking for the existance on the number in Table2.
SELECT T1.Numbers
,T1.Name
FROM Table1 T1
WHERE NOT EXISTS (SELECT 1 FROM Table2 T2 WHERE T2.Numbers = T1.Numbers)
Try this (assuming that your Numbers column are not nullable)
SELECT T1.Numbers, T1.Name
FROM Table1 AS T1
LEFT JOIN Table2 AS T2 ON T1.Numbers = T2.Numbers
WHERE T2.Numbers IS NULL;
SELECT
Table1.Numbers, Table1.Name
FROM
Table1, Table2
GROUP BY
Table1, Table2
HAVING
COUNT(*) > 1