ArcMap attribute joins generating incorrect values

Why does the attribute table have null or empty values after a join?

After performing a join, the values in the fields from the joined table might appear empty or null. Null values can be the result of several factors: Values in the specified fields for the join do not match. Joins are case sensitive, so be aware of this when using string fields to create a join.

How do I make a permanent join in Arcmap?

To make a permanent join, consider using the Join Field tool. Another way to make the join permanent is to save the joined feature layer to a new feature class or the joined table view to a new table.

Are joins permanent ArcGIS?

The join persists only for the duration of the layer. A layer can be retained by saving the ArcGIS Pro session or by saving it to a layer file using the Save Layer To File tool.

What is the difference between joins and relates in ArcGIS?

When you join two tables, you append the attributes from one onto the other based on a field common to both. Relating tables defines a relationship between two tables—also based on a common field—but doesn’t append the attributes of one to the other; instead, you can access the related data when necessary.

How do you handle NULL values in joins?

The result of a join of null with any other value is null. Because null values represent unknown or inapplicable values, Transact-SQL has no basis to match one unknown value to another. You can detect the presence of null values in a column from one of the tables being joined only by using an outer join.

Why value is getting NULL?

A NULL value is a special marker used in SQL to indicate that a data value does not exist in the database. In other words, it is just a placeholder to denote values that are missing or that we do not know.
 

Is a spatial join permanent?

While you can also select features in one layer based on their location relative to another layer, a spatial join provides a more permanent association between the two layers because it creates a new layer containing both sets of attributes.

What is the difference between cardinality and join type?

Cardinality refers to the unique relationship between the data values that have been joined. In this scenario, a join has been created to add the account code to expense details. The join relationship has been defined using the Expense Type Key which calls for a cardinality relationship of 1:n to 0:n.

What is a spatial join in ArcMap?

A spatial join involves matching rows from the Join Features to the Target Features based on their relative spatial locations. By default, all attributes of the join features are appended to attributes of the target features and copied over to the output feature class.

What do null values mean when using the join multiple tool?

When you’re using the join tool, data only joins up if it’s equal. This means, that where you have a NULL, Alteryx would only be able to join it up with another NULL in the other table.
 

What happens if we have NULL values in grouping attributes?

If a grouping column contains null values, all null values are considered equal, and they are put into a single group.
 

Why does my attribute table say null in Qgis?

By default, when you browse an Attribute Table for a Layer in QGIS and there are blank values for data the cell will show a NULL value. However, choosing Settings > Options > on the Data Sources Tab > and the Feature Attributes and Table section you can change the default value that is used for blank/null values.