Basics of SQL Part 6

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 SQL Full Outer Join


The full outer join combines the results of both left and right outer joins. The joined table will contain all records from both tables and fill in NULLs for missing matches on either side.


Syntax: select table1.col1, table2.col2...

             from table1

             left join table2

            on table1.commonfield=table2.commonfield;

            union

            select table1.col1, table.col2....

            from table1

            right join table2

            on table1.commonfield=table.2.commonfield;


Sample: select e.emp_id, e.first_name, e.last_name, d.dept_id, d.dept_name

                from emp e

                left join dept d

                on e.dept_id=d.dept_id

                union

                select e.emp_id, e.first_name, e.last_name, d.dept_id, d.dept_name

                from emp e

                right join dept d

                on e.dept_id=d.dept_id;


SQL Cross Join


- Assume there are 4 records in table 1 & 3 records in table 2


Syntax: select * from table1.cross join table2;


Subquery


A subquery is a query within another SQL query that is embedded within the where clause, from clause, & having clause.


Syntax: select column_name from table name where column_name expression operator ( select          column_name from table name);


Sample: select emp_name, dept, salary from emp where salary > (select avg(salary) from emp);


Stored Procedure


- A stored Procedure is an SQL code that we can save so that code can be reused over and over again.


Syntax: delimiter &&

              create procedure procedure name

              begin

              select column name from table name where condition

              end &&

              delimiter;


Sample: delimiter &&

               create procedure top_players()

               begin

               select name, country, goals from players where goal >6;

               end &&

               delimiter;


To run a stored procedure query


Syntax: call procedure_name();


Sample: call top_players();


#sql #storedprocedure #day6


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Contact no: 8127430702

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