KNOWLEDGE BASE

Data Missing After Joining Tables


Published: 30 Apr 2013
Last Modified Date: 30 Jan 2019

Issue

When connecting to multiple tables from a data source with table joins, the values in Tableau Desktop may be lower than expected.

Environment

Tableau Desktop

Resolution

Option 1

Add matching values to the linking fields in both tables in the data source.

Option 2

Rearrange tables in the join.
The table that contains all possible values in the linking field should be the leftmost table in the join, when the join type is Left Outer Join. (If neither table contains all possible values, this option will not work.)

Option 3

Use a Full Outer join.
Full Outer Join will include all records from both tables even when there is no matching values in the linking fields. Please note, data for which there were no matching values in the linking fields will not be related. Also note, the Full Outer join type is not available for all data sources.

For more information, see Connecting to Multiple Tables in Tableau Help.

Cause

An Inner join was used to join the tables. When using an Inner join, only values that appear in both tables are included. When using a Left join, all values from the table on the left side of the join are included.

Additional Information

SQL Joins by w3schools
Did this article resolve the issue?