What is a NULL value? What are the pros and cons

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What is a NULL value? What are the pros and cons of using NULLS ?

A NULL value takes up one byte of storage and indicates that a value is not presents as opposed to a space or zero value. It's the DB2 equivalent of TBD on an organizational chart and often correctly portrays a business situation. Unfortunately, it requires extra coding for an application program to handle this situation.

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Other Job Interview Questions

• Apart from cursor, what other ways are available to you to retrieve a row from a table in embedded SQL?
• What are correlated subqueries?
• What RDMS objects are crested with the SQL CREATE statements?
• What is the basic differnce between a join and a union?
• How do you specify and use a cursor in a COBOL program?
• How is the SUBSTR keyword used in SQL?
• Can you use MAX on a CHAR column?
• Explain an outer join ?
• What RDMS objects are required before you can create a table ?
• How would you find out the total number of row in a table?
• More...