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Joins and Relates

There are two ways to combine tables: Joins and Relates.

Joins are used for 1-to-1 relationships, or many-to-1 relationships between the attribute table and an external table.

Relates are used for 1-to-many relationships, or many-to-many relationships between the attribute table and an external table.

Table Join

Table Join:
Combines two tables based on the value of a field that can be found in both tables (a "common field").

Table Join

Join Examples in ESRI ArcMap

Example Join in ArcMap

Example of 1:1 Relationship

Results of Join Operation

Example of Many-to-1 Relationship

Many-to-1 Results

Relate Examples in ESRI ArcMap

Example of 1-to-Many Relationship: Relates

Relate ArcMap

Related Tables

Example of 1-to-Many Relationship: Relate

Summarize

Summarize creates a new table containing one record for each unique value occurring in a selected field along with statistics summarizing the data in any of the other fields.

Summarize Example

Group together all records that have the same State name. Get summary stats on the values in the rain field.

Summarize Example in ArcMap

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Additional Resources

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