Question

Which statement about SQL is true?

Select one:
a. Null values are displayed last in ascending
sequences.

b. The results are sorted by the first column in the SELECT list if the ORDER BY clause is not
provided

c. You cannot sort query results by a column that is not included the SELECT list

d. You cannot specify a column alias in an ORDER BY clause.
column

e. Date values are displayed in descending order by default.​

Answer 1

Option a)  Null values are displayed last in ascending sequences.

• Since SQL considers NULL values to be less than 0, they always appear at the top of the list when sorted in ascending order.
• If the ORDER BY clause is used, NULL values are automatically sorted lower than non-NULL values. A NULL value comes before any other non-NULL value when using the ASC order; while using the DESC order, the NULL value comes last.
• The NULL values in a column will be positioned either first or last in the result set if the ORDER BY clause is applied to that column. Depending on the database type, the result.
• Ordering. Any NULLs are regarded as having the lowest value when ordering by a field that might include NULL values. Therefore, if you order in DESC order, the NULLs will display last. One can add a column that has a higher value when the primary field is NULL in order to cause NULLs to be treated as the highest values.

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