An equijoin is a type of join in which two tables are joined based on the equality of their common columns. For example, if Table A has a column called "ID" and Table B has a column called "ID", an equijoin would be performed by matching rows in the two tables where the "ID" column values are equal.  A non-equijoin, on the other hand, is a type of join that does not rely on the equality of common columns to match rows. Instead, it uses a comparison operator such as "less than" or "greater than" to join the two tables.  For example, if Table A has a column called "Age" and Table B has a column called "Age", a non-equijoin could be performed by matching rows in Table A where the "Age" column is less than the "Age" column in Table B. Overall, the main difference between an equijoin and a non-equijoin is the type of comparison used to match rows in the two tables. Equijoins use equality, while non-equijoins use a comparison operator.