Join Statement Venn Diagram
There are four basic types of sql joins.
Join statement venn diagram. As shown in the venn diagram we need to matched rows of all tables. Inner left right and full. For this reason we will combine all tables with an inner join clause. The following query will return a result set that is desired from us and will answer the question.
The sql multiple joins approach will help us to join onlinecustomers orders and sales tables. Sql server right join. Basic sql join types. Since sql joins appear to be set based the use of venn diagrams to explain them seems at first blush to be a natural fit.
The easiest and most intuitive way to explain the difference between these four types is by using a venn diagram which shows all possible logical relations between data sets. Select c id candidate id c fullname candidate name. Select a id id a a color color a b id id b. The following statement joins the candidates table with the employees table using left join.
However like the commenters to her post i found that the venn diagrams didn t quite match the sql join syntax reality in my testing. 11 oct 2007 a visual explanation of sql joins. Because the name columns are the same in both tables you can use the using clause as shown in the following query. And the following venn diagram illustrates the result of the left join that selects rows available only in the left table.
I thought ligaya turmelle s post on sql joins was a great primer for novice developers.