COMPUTER SCIENCE AND ENGINEERING
SQL
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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no value
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zero
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spaces
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None of the above
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Detailed explanation-1: -What is a NULL Value? A field with a NULL value is a field with no value. If a field in a table is optional, it is possible to insert a new record or update a record without adding a value to this field. Then, the field will be saved with a NULL value.
Detailed explanation-2: -A null value in a relational database is used when the value in a column is unknown or missing. A null is neither an empty string (for character or datetime data types) nor a zero value (for numeric data types).
Detailed explanation-3: -The answer to that is rather simple: a NULL means that there is no value, we’re looking at a blank/empty cell, and 0 means the value itself is 0.
Detailed explanation-4: -A null value means that a real value is unknown or nonexistent. That is, no data is assigned to the column in that specific row. A null value is not a zero or a blank.
Detailed explanation-5: -A null database field means that there is no value for a given record. It indicates the absence of a value. A blank database field means that there is a value for a given record, and this value is empty (for a string value) or 0 (for a numeric value).