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1 definition found
 for outer join
From The Free On-line Dictionary of Computing (30 December 2018) :

  outer join
  full outer join
  left join
  left outer join
  right join
  right outer join
  
      A less commonly used variant of the inner join
     relational database operation.  An inner join selects rows
     from two tables such that the value in one column of the
     first table also appears in a certain column of the second
     table.  For an outer join, the result also includes all rows
     from the first operand ("left outer join"), or the second
     operand ("right outer join"), or both ("full outer join").  A
     field in a result row will be null if the corresponding input
     table did not contain a matching row.
  
     For example, if we want to list all employees and their
     employee number, but not all employees have a number, then we
     could say (in SQL-92 syntax, as used by Microsoft SQL
     Server):
  
     	SELECT employee.name, empnum.number
     	FROM employee
     	LEFT JOIN empnum ON employee.id = empnum.id
  
     or, in Sybase syntax:
  
     	SELECT employee.name, empnum.number
     	FROM employee, empnum
     	WHERE employee.id *= empnum.id
  
     The "*" on the left means "left outer join".  "*=*" would be a
     full outer join.
  
     In Oracle syntax:
  
     	SELECT employee.name, empnum.number
     	FROM employee, empnum
     	WHERE employee.id = empnum.id (+)
  
     Note that the "(+)" on the right means "left outer join".
  
     These all mean that all rows from the left-hand "employee"
     table will appear in the result, even if there is no match for
     their ID in the empnum table.  Where there is no empnum.id
     equal to a given employee.id, a result row is output anyway
     but with all result columns from the empnum table null
     (empnum.number in this case).
  
     (2004-11-12)
  

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