Hypothetically I want to merge 2 tables from different databases into one table, which includes all the data from the 2 tables:
The result would look like something like this:
Aren't the entries in the result table redundant, because there are 2 entries with Porsche and VW? Or can I just add the values in the column 'stock' because the column 'Mark' is explicit?
you need to create database link to another database here is the example on how to create database link http://psoug.org/definition/create_database_link.htm
after creating your select statement from another database should look: select * from tableA#"database_link_name"
Then you need to use MERGE statement to push data from another database so the merge statement should look something like this.
you can read about merge statement here: https://docs.oracle.com/cd/B28359_01/server.111/b28286/statements_9016.htm#SQLRF01606
merge into result_table res
using (select mark, stock, some_unique_id
from result_table res2
union all
select mark, stock, some_unique_id
from tableA#"database_link_name") diff
on (res.some_unique_id = diff.some_unique_id )
when matched then
update set res.mark = diff.mark,
res.stock = diff.stock
when not matched then
insert
(res.mark,
res.stock,
res.some_unique_id)
values
(diff.mark,
diff.stock,
diff.some_unique_id);
I hope this will help you
SELECT ROW_NUMBER() OVER (ORDER BY Mark) AS new_ID, Mark, SUM(Stock) AS Stock
FROM
(
SELECT Mark,Stock FROM Database1.dbo.table1
UNION ALL
SELECT Mark,Stock FROM Database2.dbo.table2
) RESULT
GROUP BY Mark
Try this:
Select Mark, Stock, row_number() over(order by Mark desc) from table1
union all
Select Mark, Stock, row_number() over(order by Mark desc) from table2
regardless of the data redundancy, you could use union all clause to achieve this. Like:
Select * From tableA
UNION ALL
Select * From tanleB
Make sure the total number of columns and datatype should be matched between each
Don't forget to use fully qualified table names as the tables are in different databases
SELECT
Mark
,Stock
FROM Database1.dbo.table1
UNION ALL
SELECT
Mark
,Stock
FROM Database2.dbo.table2
If these are 2 live databases and you would need to constantly include rows from the 2 databases into your new database consider writing the table in your 3rd database as a view rather.
This way you can also add a column specifying which system the datarow is coming from. Summing the values is an option, however if you ever have a query regarding a incorrect summed value how would you know which system is the culprit?
Related
How do I update one from two or more duplicate rows? I want to keep one and update the others with a new value.
Simple example tables:
from
one|two|three
----------
1|milk|water
1|milk|water
to
one|two|three
----------
1|milk|water
1|milk|sugar
http://www.ibexpert.net/ibe/index.php?n=Doc.TheMysteryOfRDBDBKEY
Select *, RDB$DB_KEY from MyExampleTable;
then
Update MyExampleTable
Set Column=Value
Where RDB$DB_KEY=xxxxx;
Another approach would be using Stored Procedure (or Execute Block) and use SQL Cursor variables. But that would require careful loop management, so you would skip one row and change 2nd, third and so on.
https://www.firebirdsql.org/file/documentation/reference_manuals/fblangref25-en/html/fblangref25-psql-coding.html#fblangref25-psql-tbl-declare-cursor
Also see examples for UPDATE ... WHERE CURRENT OF ... at
https://www.firebirdsql.org/file/documentation/reference_manuals/fblangref25-en/html/fblangref25-dml-update.html#fblangref25-dml-tbl-update
But probably most proper way would be to add unique Primary Key column to that table and then use that unique numeric ID
Don't know which version of Firebird you are using (analytic functions are supported as of version 3.0) and if the following syntax is valid (I wasn't able to verify that at the moment), you could do this:
update table
set three='sugar'
where row_number() over (partition by one, two)=1
Otherwise, another, more convoluted way to do it would be: (untested)
select one, two, three
from (
select t1.one
,t1.two
,coalesce(t2.three, t1.three) as three
,row_number() over (partition by t1.one, t1.two) as row_num
from table t1
left join (
select one, two, 'sugar' as three, 1 as row_num
from (
select distinct one, two, three
from table
group by one, two, three
having count(*) > 1
)
) t2
on t1.one=t2.one
and t1.two=t2.two
and t1.row_num=t2.row_num
)
I have two tables both with one column each. I want to copy/merge the data from those two tables into another table with both columns. So in the example below I want the data from Table1 and Table2 to go into Table3.
I used this query:
INSERT **TABLE3** (BIGNUMBER)
SELECT BIGNUMBER
FROM **TABLE1**;
INSERT **TABLE3** (SMALLNUMBER)
SELECT SMALLNUMBER
FROM **TABLE2**;
When I did this it copied the data from Table1 and Table2 but didn't put the data on the same lines. So it ended up like this:
I am trying to get the data to line up... match. So BIGNUMBER 1234567812345678 should have SMALLNUMBER 123456 next to it. If I am querying I could do this with a JOIN and a LIKE 'SMALLNUMBER%' but I am not sure how to do that here to make the data end up like this:
It doesn't have to be fancy comparing the smallnumber to the bignumber. When I BULK insert data into TABLE1 and TABLE2 they are in the same order so simply copying the data into TABLE3 without caring if SMALL is the start of BIG is fine with me.
There is no relationship at all in these tables. This is the simplest form I can think of. Basically two flat tables that need to be merged side by side. There is no logic to implement... start at row 1 and go to the end on BIGNUMBER. Start at row 1 again and go to the end on SMALLNUMBER. All that matters is if BIGBUMBER has 50 rows and SMALLNUMBER has 50 rows, in the end, there is still only 50 rows.
When I was using the query above I was going off of a page I was reading on MERGE. Now that I look over this I don't see MERGE anywhere... so maybe I just need to understand how to use MERGE.
If the order of numbers is not important and you don't want to add another field to your source tables as jcropp suggested, you can use ROW_NUMBER() function within a CTE to align a number to each row and then make a join based on them
WITH C1 AS(
SELECT ROW_NUMBER() OVER (ORDER BY TABLE1.BIGNUMBER) AS Rn1
,BIGNUMBER
FROM TABLE1
)
,C2 AS(
SELECT ROW_NUMBER() OVER (ORDER BY TABLE2.SMALLNUMBER) AS Rn2
,SMALLNUMBER
FROM TABLE2
)
INSERT INTO TABLE3
SELECT C1.BIGNUMBER
,C2.SMALLNUMBER
FROM C1
INNER JOIN C2 ON C1.Rn1 = C2.Rn2
More information about ROW_NUMBER(), CTE and INSERT INTO SELECT
In order to use a JOIN statement to merge the two tables they each have to have a column that has common data. You don’t have that, but you may be able to introduce it:
Edit the structure of the first table. Add a column named something
like id and set the attributes of the id column to autonumber.
Browse the table to make sure that theid column has been assigned
numbers in the correct order.
Do the same for the second table.
After you’ve done a thorough check to ensure that the rows are
numbered correctly, run a query to merge the tables:
SELECT TABLE1.id, TABLE1.BIGNUMBER, TABLE2.SMALLNUMBER INTO TABLE3
FROM TABLE1 INNER JOIN TABLE2 ON TABLE1.id = TABLE2.id
This question already has answers here:
Combine two tables for one output
(2 answers)
Closed 8 years ago.
I have two tables now I need a select or join command in SQL to have the third table just like image below
My two tables are like this:
I only know a simple things about join command in SQL, should I use join or something else?
I do not want have the third table in my database, I want that for a short time (something like virtual table). Please help !
You are actually looking for UNION or UNION ALL.
First of all, there is no condition on which to JOIN tables (review your documentation on JOIN) and JOIN is used for retrieving information about one logical element, let's say Event in your case, which has details stored in more tables.
Secondly, JOIN will make one result set with all of the columns of your two tables, when actually you are not trying to get all columns, but all rows.
For this you will have to use UNION or UNION ALL like this:
SELECT
EventID,
ID,
EventName,
Date,
Pic,
Privacy
FROM Table1
UNION ALL
SELECT
PLID AS EventID,
ID AS ID,
PlaceName AS EventName,
Date AS Date,
NULL AS Pic,
NULL AS Privacy
FROM Table2
In order to sort the result you get from the result set returned by the queries above you will need to wrap your above SELECT statements with another SELECT and use a WHERE clause at that level, like below:
SELECT *
FROM (SELECT
EventID,
ID,
EventName,
Date,
Pic,
Privacy
FROM Table1
UNION ALL
SELECT
PLID AS EventID,
ID AS ID,
PlaceName AS EventName,
Date AS Date,
NULL AS Pic,
NULL AS Privacy
FROM Table2) AS Result
WHERE Date > '2014-05-26'
What you're looking to do is a UNION or UNION ALL, not a join. See: http://www.w3schools.com/sql/sql_union.asp
UNION combines two tables without connecting their content. Your example shows all 4 records from the original tables unmodified.
A JOIN solution links the two tables. It's very common and you will probably use it if you're building a relational database, but it won't give you the example result.
Since the two tables don't have identical # of columns, you have to help it out here:
SELECT EventID, EventName, Date, Pic, privacy FROM [table 1]
UNION ALL
SELECT PLID, PlaceName, Date, null, null FROM [table 2]
You want to have one table from two different tables. So you need unified result set from each by renaming column in SELECT statement:
SELECT `EventID` AS `ObjectID`, `EventName` AS `ObjectName`, .... FROM table_1 ...
similary with table_2
Then combine to one result set:
SELECT `ID` AS `ObjectID`, `EventName` AS `ObjectName`, .... FROM table_1 ...
UNION
SELECT `PlaceID` AS `ObjectID`, `PlaceName` AS `ObjectName`, .... FROM table_2 ...
My mistake, I didn't take the time to examine the pictures fully. you would have to use Union since you want to return what is in both tables.
I have a basic query I use to determine the max value of a column in a table:
select A.revenue_code_id, max(A.revenue_code_version) from rev_code_lookup A
group by A.revenue_code_id
This results in ~580 rows (the entire table has over 2400 rows).
This works just fine for my query results but what I don't know is how to insert the 580 rows into a new able based on the max value. I realize this isn't the right code but what I am thinking of would look something like this:
select * into new_table from rev_code_lookup where max(revenue_code_version)
You can use the row_number() function to get the data you want. Combine with the other answer to insert the results into a table (I've made up a couple of extra columns as an example):
Select
x.revenue_code_id,
x.revenue_code_version,
x.update_timestamp,
x.updated_by
From (
Select
revenue_code_id,
revenue_code_version,
update_timestamp,
updated_by,
row_number() over (partition by revenue_code_id Order By revenue_code_version Desc) as rn
From
revenue_code_lookup
) x
Where
x.rn = 1
Example Fiddle
The insert in another table is always the same way, no matter the complexity of your select:
insert into table
[unbeliavablycomplicatedselecthere]
So in your case:
insert into new_table
select A.revenue_code_id, max(A.revenue_code_version) from rev_code_lookup A
group by A.revenue_code_id
Similarly, if you need to create a brand new table, do this first:
CREATE TABLE new_table
AS
select A.revenue_code_id, max(A.revenue_code_version) from rev_code_lookup A
group by A.revenue_code_id
This will create the corresponding table schema and then you can execute the previous query to insert the data.
I want to check my database for records that I already have recorded before making a web service call.
Here is what I imagine the query to look like, I just can't seem to figure out the syntax.
SELECT *
FROM (1,2,3,4) as temp_table
WHERE temp_table.id
LEFT JOIN table ON id IS NULL
Is there a way to do this? What is a query like this called?
I want to pass in a list of id's to mysql and i want it to spit out the id's that are not already in the database?
Use:
SELECT x.id
FROM (SELECT #param_1 AS id
FROM DUAL
UNION ALL
SELECT #param_2
FROM DUAL
UNION ALL
SELECT #param_3
FROM DUAL
UNION ALL
SELECT #param_4
FROM DUAL) x
LEFT JOIN TABLE t ON t.id = x.id
WHERE x.id IS NULL
If you need to support a varying number of parameters, you can either use:
a temporary table to populate & join to
MySQL's Prepared Statements to dynamically construct the UNION ALL statement
To confirm I've understood correctly, you want to pass in a list of numbers and see which of those numbers isn't present in the existing table? In effect:
SELECT Item
FROM IDList I
LEFT JOIN TABLE T ON I.Item=T.ID
WHERE T.ID IS NULL
You look like you're OK with building this query on the fly, in which case you can do this with a numbers / tally table by changing the above into
SELECT Number
FROM (SELECT Number FROM Numbers WHERE Number IN (1,2,3,4)) I
LEFT JOIN TABLE T ON I.Number=T.ID
WHERE T.ID IS NULL
This is relatively prone to SQL Injection attacks though because of the way the query is being built. It'd be better if you could pass in '1,2,3,4' as a string and split it into sections to generate your numbers list to join against in a safer way - for an example of how to do that, see http://www.sqlteam.com/article/parsing-csv-values-into-multiple-rows
All of this presumes you've got a numbers / tally table in your database, but they're sufficiently useful in general that I'd strongly recommend you do.
SELECT * FROM table where id NOT IN (1,2,3,4)
I would probably just do:
SELECT id
FROM table
WHERE id IN (1,2,3,4);
And then process the list of results, removing any returned by the query from your list of "records to submit".
How about a nested query? This may work. If not, it may get you in the right direction.
SELECT * FROM table WHERE id NOT IN (
SELECT id FROM table WHERE 1
);