Advanced SQL Questions

• A function returns one value and has only output parameters.
• When AUTOCOMMIT is set on, changes will be made automatically at the end of each SQL statement.
• With the UNION clause, each query involved must output the same number of columns, and they must be UNION compatible.
• The most frequently used relational operation, which brings together data from two or more related tables into one resultant table, is called an equi-join.
• Triggers are stored blocks of code that have to be called in order to operate.
• ROLLBACK WORK asks SQL to empty the log file.
• The UNION clause is used to combine the output from multiple queries together into a single result table.
• Subqueries can be nested multiple times.
• Outer join is the same as equi-join, except one of the duplicate columns is eliminated in the result table.