Part AQuestion 23Marks: 1The SELECT statement SELECT “Hi” FROM DUAL WHERE NULL=NULL; OutputsHiFALSETRUENothing

Break Down the Problem

1. Understand the components of the SQL query provided.
2. Analyze the behavior of the NULL value in SQL.
3. Determine the expected output of the statement based on SQL standards.

Relevant Concepts

1. In SQL, DUAL is a special one-row, one-column table present by default in Oracle databases.
2. The expression NULL = NULL does not evaluate to TRUE. Instead, it is treated as UNKNOWN because NULL signifies the absence of a value.

Analysis and Detail

1. The query attempts to select the string "Hi" from the DUAL table.
2. The WHERE clause checks whether NULL is equal to NULL.
3. Since the evaluation of NULL = NULL results in UNKNOWN, this means that the condition in the WHERE clause is not satisfied.
4. Therefore, the query does not return any rows.

Verify and Summarize

The evaluation of the SQL query shows that no rows meet the condition set forth in the WHERE clause. Thus, the output of the query is that no results will be returned.

Final Answer

The output of the SQL statement SELECT "Hi" FROM DUAL WHERE NULL=NULL; is Nothing.