Heres the situation. I have 2 tables here of the schema:
ID | COMPANY_NAME | DESC | CONTACT
ID | COMPANY_ID | X_COORDINATE | Y_COORDINATE
The first tabel contains a list of companies and the second contacts coordinates of the companies as mentioned.
The thing is that I want to merge the data in this table with the data in another set of tables which already have data. The other tables have similar structure but are already propopulated with data. The IDs are autoincremental.
SO if we have lets say companies marked 1-1000 in table1 and companies marked 1-500 in table 2. We need it merged such that ID number 1 in table 2 becomes ID 1001 when migrated to the other table. And side by side we would also want to migrated the entries in the coordinates table as well in such a way that they map with the new ids of the table. Can this be done in SQL or do I need to resort to using a script here for this kind of work.
i`m not sure i understand how many tables are there and who is table 1 ,2, but the problem is pretty clear. i think the easy way is:
back up all your database before you start this process
add a column to the destination table that will contain the original id.
insert all the records you want to merge (source) into the destination table, putting the original id in the column you added.
now you can update the geo X,Y data using the old ID
after all is done and good you can remove the original id column.
EDIT: in reply to your comment , i`ll add teh code here, since its more readable.
adapted from SQL Books Online: insert rows from another table
INSERT INTO MyNewTable (TheOriginalID, Desc)
SELECT ID, Desc
FROM OldTable;
Then you can do an update to the new table based on values from the old table like so:
UPDATE MyNewTable SET X = oldTable.X , Y = oldTable.Y where
FROM MYNewTable inner JOIN OldTable ON MYNewTable.TheOriginalID = OldTable.ID
Related
I have this newly created table in SQL Server with 3 columns ID, Name, Source.
Basically this table will be populated with data from other different tables, each specifically taking in their record IDs and record Names. I believe this can be easily achieved with an INSERT INTO SELECT statement.
I would like to find out on how to populate the Source column. This column is supposed to indicate which table the data came from. For example, Source in table A has 3 records, which I then copied the ID and Name columns from this table, and put it into my destination table.
At the same time, the 3 new records will have their Source column set, indicating it came from Table A. Then I will proceed to do the same for other tables.
You can use the constant string as follows:
INSERT INTO your_table
SELECT id, name, 'TableA' as source
FROM tableA
I'm trying to figure out how to insert data from Table1 into Table2, then use the newly-created ID from Table2 to update the corresponding row in Table1.
I'm using Postgres 12.4 for what it's worth
Example:
I've got two tables, e.g. users and metadata
The users tables has the following columns
| id | info | metadata_id |
The metadata table has the following columns
| id | data |
I want to migrate all of my info values from the users table into the data column of the metadata table, and update my users.metadata_id (currently blank) with the corresponding metadata.id values, essentially backfilling foreign keys.
Is there any way to accomplish this gracefully? I've got a working query which locks both tables and creates a temporary sequence to insert into the metadata.id and users.metadata_id but this seems brittle and I would need to start the sequence after the highest-existing ID in the metadata table, which isn't ideal.
I've also tried to use a data-modifying CTE with a RETURNING clause to update the users table, but couldn't get that to work.
You can't use returning here, since you need to keep track of the association of users and metadata while inserting.
I think it is simpler to first pre-generate the metadata serial of each user in a CTE, using nextval(). You can then use that information to insert into metadata and update the users table:
with
candidates as (
select u.*, nextval(pg_get_serial_sequence('metadata', 'id')) new_metadata_id
from users u
),
inserted as (
insert into metadata (id, data) overriding system value
select new_metadata_id, info from candidates
)
update users u
set metadata_id = c.new_metadata_id
from candidates c
where c.id = u.id
We need the overriding system value clause in the insert statement so Postgres allows us to write to a serial column.
Demo on DB Fiddle
I have 2 tables in my SQL database:
And I want to merge them in a way the result will be:
This is just an example for 2 tables which need to be merged into one new table (The tables contain an example data, the statement should work for any amount of data inside the tables).
The ID which got different value in CSV should be updated into the new table for example:
ID 3's value is 'KKK' and in table T is 'CCC', then what should be updated is the CSV table.
You seem to want a left join and to match to the second table if available:
select t.id, coalesce(csv.value, t.value) as value
from t left join
csv
on t.id = csv.id;
If you want this in a new table, use the appropriate construct for your database, or use insert to insert into an existing table.
I have table A with one to many relationship to table B. Whenever I do an update I create new record in table A with a new batch of records related created in table B. I had a bug in my code so when new items where being created the order of them was being reversed. I need to write a SQL query to update items in table B related to second item in table A to be the same as the ones related to first item in table A. I hope it makes any sense, will try to illustrate:
A1 -> B - 1234
A2 -> B - 4321
I want to update second set of values from table B to be the same as the ones related to A1 (1234)
You should not think of records order in database table. The only way to specify order of rows is ORDER BY clause in SELECT statement.
Make row_order or idx column in table B and put there required value for each item.
In some cases you will also get different order of B items for the first/source A record when selecting them without specifying order in ORDER BY clause.
Relational database table has no notion about neither row order nor column order.
Below i have a table where i need to get fields from one column to three columns.
This is how i would like the data to end up
Column1
Music
Column2
com.sec.android.app.music
Column3
com.sec.android.app.music.MusicActionTabActivity
Give the table a numeric autonumber id
Remove the rows with no data with a select where blank spaces or null
Find records with no point in the content with a select
Use the previous query as a source and use the id to find the id + 1 to find the next record and do the same with + 2 to find the second row
Build a table to hold the new structure and use the query as a source to insert the new created data in the new table with the 3 columns structure.
This is an example using sql server
Test table design
Data in table
Query
Look at the query from the inside. The first query inside clean the null records. Then the second query find the records with out point. This records are the reference to find the related two records. Then the id of the records with out point are used to make a query in the select adding 1 for the next record and then other query adding 2 to find the other record. Now you only need to create a table to insert this data, using this query as the source.