although i selected Full Join, i couldn't get the all rows from both tables.
how can i get all rows from both tables ? (all 12093 rows)
maybe another join type may help ?
let
Source = Table.NestedJoin(#"Beton Irsaliye Kumulatif",{"Proje No & Adi", "Firma Kodu"},#"Beton Muhasebe Kumulatif",{"Proje No & Adi", "Hesap No"},"Beton Muhasebe Kumulatif",JoinKind.FullOuter)
in
Source
Your merge is accounting for all your rows. It's just that 4 of the rows in the first table don't have matches in the second table.
Here's a simple example of what is happening. Here, I have two tables: Table1 and Table2. Both have 10 rows. In fact, both are exactly the same.
If I choose to do a Full Outer join with these, using Col1 and Col2 for matching, I'll see this:
It tells me that 10 of the rows from the first table (Table1) match rows of the second table (Table2).
Now, if I change the last two rows of Table1 (specifically, the last two rows of Col2 of Table1) like this:
Then when I try to do a Full Outer join the same way, I'll see this:
Only 8 of the rows from the first table (Table1) match rows of the second table (Table2).
But when I continue with the merge, I'll see Table1's information in a table with Table2's matching information as embedded tables in column "NewColumn" of that table:
When I then expand "NewColumn", I see all the info from Table1, as before, and all matching info from Table2, as well as rows that don't have matches between the two tables.
All rows of both tables are accounted for.
Related
I have two sources resulting from some transformation in data flow:
I have tried using join, it replicates the data no matter join I select it outputs similar stuff:
I have tried union as well but union either creates null in columns (if done by name) or rows (if done by position)
Shouldnt the join just concat the columns together because the IDs are same in both table.
This is how the desired ouput should look:
I want concat the version column to the first source so that it looks like this:
ID name value version
111 file1 0.1 3
111 file2 0.82 15
111 file3 2.2 2
Both of your source files have only one matching column (ID) and it is not unique.
When you join both sources on the ID column, each row of source1 joins with all the matching rows of source2.
Here, your row1 (111) of source1 joins with all 3 matching rows (111) of source2, hence it results in 9 rows with different version values for each row in source1.
To get only 3 rows as your expected results, you need a unique matching row in each source.
Add window transformation for both sources and get the rowNumber() based on the ID column.
Source1->window1:
Window1 data preview:
Source2->window2:
Window2 data preview:
Add join transformation to join data from window transformations on ID and rank columns.
Join data preview:
Add select transformation to remove the unwanted columns.
Select data preview:
That is expected with a join. For example, when you join tables in SQL, you also supply the target projection as part of the select statement. What you need to do here is add a Select transformation after your Join transformation. In there, you will reduce the projection to just the columns that would like to retain. You'll be able to choose which side (left or right) you would like to keep for the ID column.
I have two tables: A (525,968 records) and B (517,831 records). I want to generate a table with all the rows from A and the matched records from B. Both tables has column "id" and column "year". The combination of id and year in table A is unique, but not in table B. So I wrote the following query:
SELECT
A.id,
A.year,
A.v1,
B.x1,
B.e1
FROM
A
LEFT JOIN B ON (A.id = B.id AND A.year = B.year);
I thought the result should contain the same total number of records in A, but it only returns about 517,950 records. I'm wondering what the possible cause may be.
Thanks!
First of all, I understand that this is an example, but postgres may hava an issues with capital letters in the table names.
Secondly, it may be a good idea to check how exactly you calculated 525,968 records. The thing is - if you use sime kind of client of database administration / queries - it may show you different / technical information about tables (there may be internal row counters in postgres that may actually differ from the number of records).
And finally to check yourself do something like
SELECT
count("A".id)
FROM
"A"
Example scenario:
TABLE_A contains a column called ID and also contains duplicate rows. There is another table called ID_TABLE that contains IDs. Assuming no duplicates in ID_TABLE -
If I do:
SELECT * FROM TABLE_A
INNER JOIN ID_TABLE ON ID_TABLE.ID = TABLE_A.ID
There will be duplicates in the result set. However, if I do:
SELECT * FROM TABLE_A
WHERE TABLE_A.ID IN (SELECT ID_TABLE.ID FROM ID_TABLE)
There will not be any duplicates in the result set.
Does anyone know why the JOIN clause allows duplicates while the IN clause does not? I had thought they did the same thing.
Thanks
It's not that it's allowing duplicates. By joining the two tables, you are creating a product from table 1 and table 2, so if TABLE_A has two records for ID=1 and ID_Table has 1 record, the resulting product is two records. Using IN doesn't cause a multiplication of records, even if the value is listed in the IN clause multiple times as you are only getting the unique records matching the values within the IN clause.
I have two tables, table1 and table2, both of which contain columns that store postgis geometries. What I want to do is see where the geometry stored in any row of table2 geometrically intersects with the geometry stored in any row of table1 and update a count column in table1 with the number of intersections. Therefore, if I have a geometry in row 1 of table1 that intersects with the geometries stored in 5 rows in table2, I want to store a count of 5 in a separate column in table one. The tricky part for me is that I want to do this for every row of column 1 at the same time.
I have the following:
UPDATE circles SET intersectCount = intersectCount + 1 FROM rectangles
WHERE ST_INTERSECTS(cirlces.geom, rectangles.geom);
...which doesn't seem to be working. I'm not too familiar with postgres (or sql in general) and I'm wondering if I can do this all in one statement or if I need a few. I have some ideas for how I would do this with multiple statements (or using for loop) but I'm really looking for a concise solution. Any help would be much appreciated.
Thanks!
something like:
update t1 set ctr=helper.ctr
from (
select t1.id, count(*) as cnt
from t1, t2
where st_intersects(t1.col, t2.col)
group by t1.id
) helper
where helper.id=t1.id
?
btw: Your version does not work, because a row can get updated only once in a single update statement.
I am developing a t-sql query to return left join of two tables, but when I just select records from Table A, it gives me only 2 records. The problem though is when I left join it Table B, it gives me 4 records. How can I reduce this to just 2 records?
One problem though is that I am only aware of one PK/FK to link these two tables.
The field you are using for the join must exist more than once in table B - this is why multiple rows are being returned in the join. In order to reduce the row count you will have to either add further fields to the join, or add a where clause to filter out rows not required.
Alternatively you could use a GROUP BY statement to group the rows up, but this may not be what you need.
Remember that the left join brings you null fields from joined table.
Also you can use select(distinct), but i can't see well you issue. Can you give us more details?