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Questions tagged [anti-join]

An anti-join, also called an excluding-join or left-outer-join, comes from requesting data from a table where some value is not in another table

Formal Definition

The antijoin, written as R ▷ S (where R and S are relations), is similar to the semijoin, but the result of an antijoin is only those tuples in R for which there is no tuple in S that is equal on their common attribute names.

Venn Diagram

anti-join

SQL Phrasing

SELECT <select_list>
FROM TableA A
LEFT JOIN TableB B
ON A.Key = B.Key
WHERE B.Key IS NULL

Related to

References:

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How do I find records that are not joined?

I have two tables that are joined together. A has many B Normally you would do: select * from a,b where b.a_id = a.id To get all of the records from a that has a record in b. How do I get just the records in a that does not have anything in b?
Sixty4Bit
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Anti-Join Pandas

I have two tables and I would like to append them so that only all the data in table A is retained and data from table B is only added if its key is unique (Key values are unique in table A and B however in some cases a Key will occur in both table…
Ayelavan
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Checking whether an item does not exist in another table

My tables are set up something like this: table name: process fields: name, id_string table name: value_seach fields: id_string, value I want to construct a select statement that will display all of the process names (with it's respective…
user906153
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Spark Dataset when to use Except vs Left Anti Join

I was wondering if there are performance difference between calling except (https://spark.apache.org/docs/2.1.0/api/java/org/apache/spark/sql/Dataset.html#except(org.apache.spark.sql.Dataset) and using a left anti-join. So far, the only difference I…
alexgbelov
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No applicable method for 'anti_join' applied to an object of class "factor"

I want to Identify the rows present in dataframe1 which are not present in dataframe2 based on a particular column. I have used the below code to get the desired information. diffId <- anti_join(dat$ID,datwe$ID) Unfortunately, I have encountered…
Prradep
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How to find non-existing data from another Table by JOIN?

I have two tables TABLE1 which looks like: id name address 1 mm 123 2 nn 143 and TABLE2 w/c looks like: name age mm 6 oo 9 I want to get the non existing names by comparing the TABLE1 with the TABLE2. So…
Blair Yumi
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why left_anti join doesn't work as expected in pyspark?

In a dataframe I'm trying to identify those rows that have a value in column C2 that does not exist in column C1 in any other row. I tryed the following code: in_df =…
heinzK
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Broadcast left table in a join

This is my join: df = df_small.join(df_big, 'id', 'leftanti') It seems I can only broadcast the right dataframe. But in order for my logic to work (leftanti join), I must have my df_small on the left side. How do I broadcast a dataframe which is on…
ZygD
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MySQL Anti Join

I have two Tables: Course: Id, Name Teacher: IdUser, IdCourse, IdSchool Now, for Example I have a user with the id 10 and a School with the id 4 . I want to make a Select over all the Cousrses in the table Course, that their Id are NOT recorded in…
user3477008
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Does C# linq support "anti join" semantics?

I've googled a little while and didn't find a direct anti-join semantics example. How to do this in C# LINQ as an example?
Troskyvs
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Postgres ANTI-JOIN needs Table-Scan?

I need an ANTI-JOIN (not exists SELECT something from table.../ left join table WHERE table.id IS NULL) on the same table. Acutally I have an index to serve the not exists question, but the query planner chooses to use a bitmap heap scan. The table…
Franz Kafka
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How to Anti Join in MSSQL when the join depends on data from a 3rd table

Here is my situation. PayTable +-------+------+--------------+ | Craft | Job | sequence | +-------+------+--------------+ | 400 | 1 | 1 | +-------+------+--------------+ | 401 | 2 | 2 …
Jeremy Keczan
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SELECT statement comparing multiple fields from multiple tables

I have to two seperate tables (Table A and Table B). Table A has about 15 columns, the only ones of significance are [First Name] and [Last Name]. Table B has many more columns, and again the only ones I care about are FirstName and LastName (Table…
user1096207
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Alternative for left-anti join that allows selecting columns from both left and right dataframes

I need to use the left-anti join to pull all the rows that do not match but, the problem is that the left-anti join is not flexible in terms of selecting columns, because it will only ever allow me select columns from the left dataframe... and I…
Vanessa_C
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anti join pandas data frames at different levels in python

I am having two pandas data frames say df1 and df2. df1 has 6 variables and df2 has 5 variables. and first variable in both the data frames are in string format and reaming are in int format. i want to identify the mismatched records in both data…
Neeraja Bandreddi
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