We refer to a join as a self-join when…
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We are joining two tables only
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we are using left and right join together
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we are joining table to itself
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we are joining more than 2 tables
A self-join refers to a standard inner or outer join operation where a table is joined with itself. This is typically used to query hierarchical data stored within a single table by using aliases.
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.