sql learning

  • The clause combines UNION data in SQL

    The clause combines UNION data in SQL

    in sql, you can combine the same structured data from multiple tables into one query using the union and union all operators.
  • Constraints in SQL

    Constraints in SQL

    constraint is the rule applied on the data columns of a table.
  • SELF JOIN in SQL

    SELF JOIN in SQL

    each join operation must have two tables, but there are cases where you have to perform join on the same table, but you can call this join operation self join.