1. What is a select statement? Name the two required components of a select statement.
2. What is a schema?
3. What is the DUAL table? Why is it used?
4. What does NULL mean in the context of Oracle SQL?
5. What is a column alias? For what situations might column aliases be useful?
6. What are two ways to define aliases for columns?
7. What is column concatenation? What special character sequence is used to concatenate columns?
8. How can a user put row data returned from a select statement in order? What are the various sort orders
that can be used with this option?
9. What are the two ways to specify the column on which sort order should be defined?
10. What is a where clause? On what principle does this clause operate to determine which data is selected?
11. Identify some of the character, number, and date functions available in SQL. What are two functions that
allow you to transform column values regardless of the datatype?
12. What are other types of functions that perform operations on columns of specific datatypes?
13. What is the purpose of the nvl( ) function? What datatypes does it accept? What is the purpose of a decode(
) statement? What datatypes does it accept?
14. Name some character functions? Can two functions be combined? Why or why not?
15. Name some single-value number functions. What types of applications are these functions typically used in?
16. What function is used to determine the size in bytes of a given value or column?
17. Which date functions return information in the DATE datatype? Which one returns information in a datatype
other than DATE?
18. How are dates stored in Oracle?
19. Identify some conversion functions. Which conversion functions are commonly used?
20. What is a table join? How is a table join produced?
21. How does an outer join remedy the situation where a lack of corresponding values in the shared column of
two tables causes rows from neither table to be selected? What is the special character used to denote
outer joins?
22. What is a self join? How might a self join be used?
23. How are group functions incorporated into select statements? How many rows of output can usually be
expected from a query using a group function?
24. What is ROWID? Is ROWID stored in a table?
25. How is the group by clause of a select statement used? (With Example)
26. Identify some situations where statements containing the group by clause return errors.
27. What is the having clause, and what function does it serve?
28. How can the user specify values to fulfill having criteria without actually knowing what the values themselves
are?
29. What is a subquery? When might a user want to incorporate a subquery into a database select statement?
30. What are some situations where a where clause may be sufficient in place of a subquery?
31. What is variable scope? What is a local variable? What is a global variable?
32. What is the distinct keyword, and how is it used?
33. Can you use the order by clause within select statements with subqueries? Why or why not?
34. What special character is used to specify a runtime variable? How does Oracle prompt for runtime variable
change?
35. What are three types of data relationships?
36. What is functional dependency?
37. What is required of two tables in order for the tables to be related?
38. What is a relational database model?
39. What are the components of a relational database? How are they used?
40. What is an entity-relationship diagram and how is it read?
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