How do I merge a column from one table into the column of another table that has missing entries?

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MathWorks Support Team
编辑： MathWorks Support Team 2014-11-10
I have two tables with different column names and different number of rows. Column 3 of table A for example is missing some entries that are present in column 2 of table B. I want to add the missing entries from B into A based on the values in another column, say column 2 of table A. However, not all the same entries are present in the two tables for the key.
For example, the two tables look like this:
 
A = table({'John','Jane','Jim','Jerry','Jill'}',[1;2;1;3;1], {'', '', '', 'Mat',''}', ...
    'VariableNames',{'Employee' 'Department', 'Manager'})
 
B = table([1 2]',{'Mary' 'Mike'}',...
    'VariableNames',{'Department' 'Manager'})
 
If I try using the "join" function, I get an error because there are more Departments in A than in B.
  >> join(A,B)
Error using table/join (line 128)
The key variables for A and B cannot contain any missing values.
  How can I do this?

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采纳的回答

MathWorks Support Team
There are two possible solutions depending on the output you expect to see:
1. Using "outerjoin"
Using the "outerjoin" function and specifying the variable "Keys" to use to merge the tables produces the output:
 
C = outerjoin(A,B,'Keys','Department','MergeKeys', 1)
 
2. Using "ismember"
Using the "ismember" function to determine the matching rows in A and B and adding the missing entries in A from B produces the output:
  [idxA, idxB] = ismember(A.Department, B.Department);
A(idxA,'Manager') = B(idxB(idxA),'Manager');
 

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