To answer this question, we need to understand what a self-join is.

A self-join occurs when we join a table to itself. This means that we treat the same table as two separate entities and perform a join operation on them.

Option A) We are joining two tables only - This option is incorrect because a self-join involves joining a table to itself, not two separate tables.

Option B) We are using left and right join together - This option is incorrect because a self-join can be performed using any type of join, not just a combination of left and right join.

Option C) We are joining table to itself - This option is correct because a self-join is defined as joining a table to itself.

Option D) We are joining more than 2 tables - This option is incorrect because a self-join involves joining a table to itself, not multiple tables.

Therefore, the correct answer is option C) We are joining table to itself.

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To answer this question, you need to understand the correct syntax for the TRUNCATE statement in SQL. Let's go through each option to understand why it is correct or incorrect:

A) TRUNCATE Sales TABLE - This option is incorrect because the correct syntax for the TRUNCATE statement does not include the keyword "TABLE" after the table name. The correct syntax is "TRUNCATE TABLE Sales."

B) TRUNCATE * FROM TABLE Sales - This option is incorrect because the TRUNCATE statement does not use the "FROM" keyword or the asterisk (*) to specify columns or rows to be truncated. The correct syntax is "TRUNCATE TABLE Sales."

C) TRUNCATE TABLE Sales - This option is correct because it follows the correct syntax for the TRUNCATE statement in SQL. The "TRUNCATE TABLE" syntax is used to delete all rows from a table without logging individual row deletions. The "Sales" in this statement is the name of the table to be truncated.

D) TRUNCATE * FROM COLUMN Sales - This option is incorrect because the TRUNCATE statement does not use the "FROM" keyword or the "COLUMN" keyword. The correct syntax is "TRUNCATE TABLE Sales."

The correct answer is C. This option is correct because it follows the correct syntax for the TRUNCATE statement in SQL, which is "TRUNCATE TABLE [table_name]". In this case, the table name is "Sales."

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To answer this question, you need to understand where sub-queries can be nested.

Option A) UPDATE, DELETE, INSERT and SELECT statements - This option is correct because sub-queries can be nested in all of these statements. Sub-queries are used to retrieve data from one table and use it in another table or perform operations on it.

Option B) UPDATE statements only - This option is incorrect. Sub-queries can be nested in UPDATE statements, but they can also be used in other types of statements.

Option C) DELETE statements only - This option is incorrect. Sub-queries can be nested in DELETE statements, but they can also be used in other types of statements.

Option D) INSERT statements only - This option is incorrect. Sub-queries can be nested in INSERT statements, but they can also be used in other types of statements.

The correct answer is A) UPDATE, DELETE, INSERT and SELECT statements. This option is correct because sub-queries can be nested in all of these statements.

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• Wrong explanation