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Tag: join

Difference between natural join and inner join

What is the difference between a natural join and an inner join? Answer One significant difference between INNER JOIN and NATURAL JOIN is the number of columns returned. Consider: The INNER JOIN of TableA and TableB on Column1 will return The NATURAL JOIN of TableA and TableB on Column1 will return: The repea…

how to avoid duplicate on Joining two tables

This result is 2 times A even after using disticnt . My expected result will have only one A. if i remove row_number() over() as rownum its working fine. Why this is happening ? how to resolve. AM using DB2!! Answer There are two rows in marks Table with id = 1 and mark = 50.. So you will get

Count number of occurrences in SQL

I have a table with the following structure: (table_name, column_name) and for each row in this table I need to query the column_name in the table_name and do a COUNT(column_name) GROUP BY …

SQL statement to get all customers with no orders

I have a typical Persons table and an Orders table defined in such a way that I can do JOIN query as the following to return Orders for all Persons. The question is, how do I write a statement that would return all Persons with NO Orders? I’m using mysql. Thank all in advance. Answer You may want to use

Left Outer join and an additional where clause

I have a join on two tables defined as a left outer join so that all records are returned from the left hand table even if they don’t have a record in the right hand table. However I also need to include a where clause on a field from the right-hand table, but…. I still want a row from the

Oracle join query

There are three tables in my db: ITEM_MASTER, PRICE_MASTER and COMP_MASTER. ITEM_MASTER STORE_CODE ITEM_CODE ITEM_DESC 011 914004 desccc PRICE_MASTER STORE_CODE ITEM_CODE COMP_CODE …

Join one row to multiple rows in another table

I have a table to entities (lets call them people) and properties (one person can have an arbitrary number of properties). Ex: People Properties I would like to write an efficient select that would select people based on age and return all or some of their properties. It’s also acceptable to return one …

SQL Inner Join On Null Values

I have a Join Isnull in a Join like this makes it slow. It’s like having a conditional Join. Is there any work around to something like this? I have a lot of records where QID is Null Anyone have a work around that doesn’t entail modifying the data Answer You have two options or easier