What are table constraints ? What are column constraints ? How are these two different ?

Table constraints are rules or conditions applied to an entire table in a database. They are defined when creating or altering a table's schema.

Column constraints are rules or conditions applied to individual columns within a database table. They are specified at the column level when creating or altering a table's schema.

The difference between the two is that column constraints apply only to individual columns, whereas table constraints apply to groups of one or more columns.