1.While in a Table Compare session, choose Session | Session Settings to open the Session Settings dialog.
2.Click the Format page.
Each line in the display represents a comparison column and shows the following information:
•Comparison 
if key, column number and column name
•Left file column number and sample data if available
•Right file column number and sample data if available
•Handling summary of column comparison
To control the alignment of rows
Define as many columns as keys as necessary to uniquely identify each row. By default, the first column is the only one defined as a key. To define a column as a key, select the appropriate line, click the Edit button, select the Key checkbox, and click OK. If multiple keys are defined, precedence follows the order in the comparison. If no keys are defined, the alignment will use all of the columns to uniquely identify each row.
To control the alignment of columns
By default, the comparison assumes the columns of the files are in the same order. To change the comparison order of a column in the left file, select the appropriate line under Left file and click the Move Up 
or Move Down 
button as necessary. If you select under Comparison instead, those buttons will change the position of the comparison column itself.
To prevent a column in the left file from being compared, select the appropriate line under Left file and click the Remove button. If you select under Comparison instead, this button will prevent its file columns from being compared and delete this comparison column definition.
To restore a removed column from the left file, select under Left file, click the Insert button, select items in the Insert Columns dialog and click OK. Click the Tidy button to remove any blank lines from the list.
To control the names of columns
By default, column names are automatically determined from the left or right file.
To give a column a specific name, select the appropriate line, click the Edit button, change the Name, and click OK.
To revert all columns to automatic naming, choose Reset Names from the list's right-click menu.
If left file data is available, you can choose Fill Names Using Left File from the list's right-click menu to force the names to use those found in the left file. Fill Names Using Comparison will force the names to use those that would be automatically determined.
To control how column data is compared
Select the appropriate line and click the Edit button to open the Column Handling dialog. To change the default Handling settings, click the Edit Default button.
