why we needed join in database ?
2007-07-01 21:23:57 · 4 answers · asked by Amit H 1 in Computers & Internet ➔ Programming & Design
you have two or more tables that are related to each other conceptually and you wanna get data that lies in that conceptual relationship.
for example you have employee names, codes and marital status in table A and employees' codes and salaries in another table like B.
Now imagine if you want the codes and names of those married people with salaries less than some x dollars per month so that the company can help them.
here you need to join the two tables.
Hope this has helped you
good luck :)
2007-07-01 21:45:09 · answer #1 · answered by njm 3 · 0⤊ 0⤋
In most queries, we will want to see data from two or more tables. To do this, we need to join the tables in a way that matches up the right information from each one to the other
2007-07-02 04:33:42 · answer #2 · answered by abd 5 · 0⤊ 0⤋
I perform joins constantly. If you ever need information from a parent and a child tables. You join the tables on their primary / foriegn key and select the fields from the two tables you want to see.
2007-07-02 04:35:21 · answer #3 · answered by Michael M 6 · 0⤊ 0⤋
To produce one step queries instead of having to use multi step queries with intermediate files or temporary database tables.
2007-07-02 04:33:33 · answer #4 · answered by bambamitsdead 6 · 0⤊ 0⤋