SQL Self Join Example
Access self join: In this update query example we use the self join query technique to update each employee’s salary by 10%. There are at least two ways to do this update.Example c) (below) is supposed to work but I get errors in Access. It is called a correlated subquery – if you can tell me what is wrong with it I’d really appreciate it.
Self Join Query Code:
a) Update M_Emp as A INNER JOIN M_Emp as B ON A.Emp_ID = B.Emp_ID SET A.Salary = B.Salary*1.1
b) Update M_Emp as A, M_Emp as B Set A.Salary=B.Salary * 1.1
c) Update M_Emp as A set A.Salary = (Select Salary * 1.1 from M_Emp Where M_Emp.Emp_ID = A.Emp_ID)
Note: I have added a another feature to this self join query example – Aliases. Aliases are where you use ‘as’ to establish a short nickname for a table or a field. This alias feature helps when you have long table names or are trying to do a correlated subquery.
Additional One Table/Same Table Update Examples:
MS Access 2000 Through Access 2016 & Office 365
Microsoft Office VBA, MS Access 2003, 2007, 2010, 2013, 2016