join types in sql code example
Example 1: sql server joins
SELECT Orders.OrderID, Customers.CustomerName, Orders.OrderDate
FROM Orders
INNER JOIN Customers ON Orders.CustomerID=Customers.CustomerID;
Example 2: data types in sql
• number(num) - whole numbers up to num digits
• number(num,num2) - num whole numbers up to num2 decimals
• char(num) - fixed length character/string
• varchar2(num) - used for varying length data
• date - full date
• currency - used for prices
Example 3: joins in sql
INNER JOIN:
is used when retrieving data from multiple
tables and will return only matching data.
LEFT OUTER JOIN:
is used when retrieving data from
multiple tables and will return
left table and any matching right table records.
RIGHT OUTER JOIN:
is used when retrieving data from
multiple tables and will return right
table and any matching left table records
FULL OUTER JOIN:
is used when retrieving data from
multiple tables and will return both
table records, matching and non-matching.
INNER JOIN :
SELECT select_list From TableA A
Inner Join TableB B
On A.Key = B.Key
LEFT OUTER JOIN :
SELECT select_list From TableA A
Left Join TableB B
On A.Key = B.Key
(where b.key is null)
RIGTH OUTER JOIN :
SELECT select_list From TableA A
Right Join TableB B
On A.Key = B.Key
FULL JOIN :
SELECT select_list From TableA A
FULL OUTER Join TableB B
On A.Key = B.Key
Example 4: join types in sql
INNER JOIN:
is used when retrieving data from multiple
tables and will return only matching data.
LEFT OUTER JOIN:
is used when retrieving data from
multiple tables and will return
left table and any matching right table records.
RIGHT OUTER JOIN:
is used when retrieving data from
multiple tables and will return right
table and any matching left table records
FULL OUTER JOIN:
is used when retrieving data from
multiple tables and will return both
table records, matching and non-matching.