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Tag: left-join

SQL – left join performs cartesian/multiplies matched rows

I have a very simple example but can’t understand why final result of LEFT JOIN returns 4 rows with value 3. Do I understand correctly that LEFT returns as many results for each row in left table as many matches it finds in the right table? (nb of rows times x nb of rows in right table). If yes, why

How to SUM two SUMmed SQL result fields

I have a simple table structure holding records of reagent_bottles and reagent_aliquots. Aliquots are created from bottles, and an aliquot record got a foreign key, bottle_id, to a bottles id. To get the total volume of a particular reagent (counting both the volume in the bottles and the volume in the aliquots), the following query does the job, partly: returns

Left join without using view

I have a table structure similar to this: users | id | name | |—-|——–| | 1 | jane | | 2 | john | client | id | name | user_id | |—-|————|———| | 1 | client 1 |…

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