When you use a Microsoft Excel worksheet as a data source in Microsoft
Query, and you attempt to create a join between two fields of seemingly
similar data types, Microsoft Query may generate the following warning
Columns <name> and <name> that you are about to join are of
different types. Create the join anyway?
If you choose Yes to this option, you receive either of the following
Microsoft Query version 1.0
Microsoft Query version 2.0
Reserved error(-3079); there is no message for this error.
Microsoft Query version 8.0
Type mismatch in JOIN expression.
This behavior occurs regardless of the number of "Rows To Scan" you
specified when you set up the data source.
This problem occurs because the two apparently similar fields may be
evaluated as being of different data types. This difference in type causes
an error and prevents you from completing the join.
The Microsoft Excel Open Database Connectivity (ODBC) driver provides
an option called Rows To Scan. This option specifies the number of rows
to scan to determine the data type of each column. The data type is
determined given the maximum number of kinds of data found. If data is
encountered that does not match the data type guessed for the column,
the data type will be returned as a NULL value. The ODBC.HLP file
included with the ODBC driver includes the following information:
For the Microsoft Excel driver, you may enter a number from 1 to 16
for the rows to scan; however, the value will always default to 1.
(A number outside the limit will return an error.)
This information is incorrect. The Rows To Scan option will always use
the first eight rows of data to determine the data type of a given
field regardless of the number of rows specified. In the case where the
first 8 rows contain four numeric and four text values, the data type
for the column will default to Number.
To ensure that Microsoft Query accesses your Microsoft Excel data properly,
make sure that all values in a particular column are of the same data type.
Do not mix text and numeric data in a single column. If you need to have
mixed data in a field, format the column in Microsoft Excel as Text (on the
Format menu, click Cells, and select the Text option on the Numbers tab)
before you enter data.
Microsoft is researching this problem and will post new information
here in the Microsoft Knowledge Base as it becomes available.
For more information about Rows To Scan, click Help in the Add Data
Source dialog box. In ODBC Help, click the Index tab, and type the
rows to scan