Oracle SQL and PLSQL Inteview Questions
Posted on 2013-01-22
Can I have a list of very commonly asked SQL and PLSQL Interview QUestions & Answers please....
For Basic SQL:
How do you convert a date to a string? To_char. A bonus would be that they always include a format mask.
What is an aggregate function? I'm looking for "grouping", sums or counts, etc.
What is an interval? Specifies a period of time.
What is a nested subquery? A subquery in a where clause.
What is the dual table? A single row table provided by oracle for selecting values and expressions.
For Basic PL/SQL:
Describe the block structure of PLSQL. Declaration, Begin, exception, end.
What is an anonymous block? Unnamed PL/SQL block.
What is a PL/SQL collection? PL/SQL Table, Varray, PL/SQL Array, etc.
What is the difference between an explicit cursor and a select into. You might get something about performance but that's a myth. An explicit cursor is just more typing. A cursor for loop would be used to return more than a single row.
Why would you choose to use a package versus straight procedures and functions? I look for maintenance, grouping logical functionality, dependency management, etc. I want to believe that they believe using packages is a "good thing".