Question

What are some useful SQL statements that should be known by all developers who may touch the Back end side of the project?

(Update: just like in algorithm, we know there are sorting problems, shuffling problems, and we know some solutions to them. This question is aiming at the same thing).

For example, one I can think of are:

Get a list of Classes that are not
registered by any students. (Outer
join and check whether the match is
NULL, or by Get from Classes table,
all ClassIDs which are NOT IN (a
subquery to get all ClassIDs from the
Registrations table))

Are there some SQL statements that should be under the sleeve of all developers that might touch back end data?

Answer 1

Hmm generalizing what types of queries you should be able to write.

1. First a straight up select with no
   joins (and no select *)
2. You should know how to combine two
   or more tables and get records that
   are in all the tables
3. You should know how to combine two
   or more tables and get records that
   are in all the tables but return
   only one record from the table with
   the many side of the one-to-many
   relationship
4. You should be able to get the
   records in one table but not in an
   associated table
5. You should be able to Aggregate data
   for a report
6. You should be able to insert one
   record to a table
7. You should be able to update one
   record in a table
8. You should be able to delete one
   record in a table
9. You should be able to insert a group
   of records to a table without a
   cursor
10. You should be able to update a
    group of records in a table without
    a cursor
11. You should be able to delete a
    group of records in a table without
    a cursor
12. You should be able to perform
    multiple actions in one transaction
    and handle error trapping
13. You should be able to create union
    of records and know when to use
    UNION vice UNION ALL
14. You should be able to vary the data
    for one field based on some
    criteria (using CASE)
15. You should be able to write an IF
    Statement.

Well that’s what springs to mind immedaitely. This is for a beginner SQL developer of course. This includes nothing I would consider advanced.