SQL Scripting

In testing point of view you need to know SQL Queries like Select statement for retrieving data from database, Insert statement
for inserting the values in database and as a tester you need not worry about update, drop, delete, they
are not going to give you and go for Joins like inner-join, outer-join, stored procedure, these
will help you a lot, so go and practice, All the Best.

For SQL Scripting, you need to know to following SQL commands/concepts:
1. Select
2. Insert
3. Update
4. Delete
5. Drop
6. Alter
7. Join(Inner,outer)
8. Views

These are the most widely used as per testing perspective.