The top row must contain the labels, and data values must begin on the second row.
Only letters, numbers, and underscores are permitted in the header row.
Headers must not begin with a number.
File formats permitted:
Excel Workbook 97-2003 (.XLS)
Text Delimited (.TXT or .CSV)
Microsoft Access 2000 or 2002-2003 (.MDB)
Performing the Tabular Join
One table will inherit the attributes (Target Table) of a second table (Join Table) based on a common field.
Right-click on the Target Table and select Joins & Relates/Join
Ensure 'Join attributes from a table' is selected.
Enter required information and OK
Open the attribute table of the Target Table and scroll to the right to see the joined attributes
If you can not select the join field in the Join Table, the most likely problem is a field type conflict.
Rule: Can join Text field to Text field, or Numeric field to Numeric field, but not Text to Number.
Fix: Add a new field in the Target Table and define the new field as needed (Double for numeric or Text for text). Use the Field Calculator to copy the old field values into the new field.
If you are 100% sure with no doubts that the two join fields match but the reulting join are all NULLS, the most likely problem is an illegal character in the Join Table's header row.
Fix: Remove all illegal characters from header row. If you are 100% sure without a doubt that there are no illegal characters, open the table in Excel and use the Find or Replace tool to hunt for invisible empty spaces. Common hidden culprits are spaces at the beginning or the end of a field header.