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Technical Sample Questions

Oracle Sample Questions : Oracle SQL

21. What are the most important DDL statements in SQL?

    Answer: The most important DDL statements in SQL are:

    • create table-creates a new database table
    • alter table-alters (changes) a database table
    • drop table-deletes a database table
    • create index-creates an index (search key)
    • drop index-deletes an index

22. What are the different SELECT statements?

    Answer: The SELECT statements are:

    • SELECT column_name(s) FROM table_nameSELECT DISTINCT column_name(s) FROM table_name
    • SELECT column FROM table WHERE column operator value
    • SELECT column FROM table WHERE column LIKE pattern
    • SELECT column,SUM(column) FROM table GROUP BY column
    • SELECT column,SUM(column) FROM table GROUP BY column HAVING SUM(column) condition value

23. What are the INSERT INTO Statements?

    Answer: The INSERT INTO statements are:

    • INSERT INTO table_name VALUES (value1, value2,....)
    • INSERT INTO table_name (column1, column2,...) VALUES (value1, value2,....)

24. Write theUpdate Statement?

    Answer: UPDATE table_name SET column_name = new_value WHERE column_name = some_value

25. What are the Delete Statements?

    Answer: These are:

    • DELETE FROM table_name WHERE column_name = some_value

    Delete All Rows:

    • DELETE FROM table_name
    • DELETE * FROM table_name

26. how we can sort the Rows?

    Answer: There are mainly three types:

    • SELECT column1, column2,...FROM table_name ORDER BY columnX, columnY,..
    • SELECT column1, column2,...FROM table_name ORDER BY columnX DESC
    • SELECT column1, column2,...FROM table_name ORDER BY columnX DESC, columnY ASC

27. Explain IN operator.

    Answer: The IN operator may be used if you know the exact value you want to return for at least one of the columns.

    SELECT column_name FROM table_name WHERE column_name IN (value1,value2,..)

28. Explain BETWEEN...AND

    Answer: SELECT column_name FROM table_name WHERE column_name BETWEEN value1 AND value2 The values can be numbers, text, or dates.