Salesforce Bucket Field Limitations in Reporting

What Is a Bucket Field?

A Bucket Field is a report field that groups values from an existing field into named buckets. You can then display the grouped values by name in your report. For example, on an Accounts report, you can create a Bucket column named Emp Size based on the Number of Employees field and group records into Small, Medium, or Large.
For instructions on creating a Bucket column, see Categorize Data with Bucket Columns.

Limits

• Each report can include up to 5 Bucket fields.
• Each Bucket Field can contain up to 20 named groupings.
• Each grouping can contain up to 20 selected values. (Does not include the use of "Other" as permitted within the Bucket Field setup.)
• Total values allowed per Bucket Field — There is an overall query limit that is generally reached when bucket fields contain approximately 42–45 values. Exceeding this limit results in the error: "The query for these buckets is too complex. Remove one or more buckets and retry."
• Editions: Available only in Developer, Enterprise, Performance, and Unlimited Editions.

Limitations

• "Query is too complex" error — When you exceed the overall Bucket Field limit (usually around 42–45 values for the whole bucket), you receive the error: "The query for these buckets is too complex. Remove one or more buckets and retry."
• Reusing Bucket Fields in multiple reports — Bucket Fields can only be used in the report where they were created. To use a Bucket Field in another report, recreate it for each additional report or create a separate formula field on the object.
• Custom Summary Formulas — Bucket Fields cannot be created against Custom Summary Formulas.
• Reporting Snapshots — Bucket Fields are available for Reporting Snapshots only if the source report is tabular.
• Historical trend reporting — Bucket Fields cannot be created in Historical Trending reports.
• Record Type — The standard Record Type field cannot be bucketed.
• Bucket size — Buckets with values that exceed more than 1,000 characters in aggregate do not appear in dashboard components when used in the "Group By" field.
• Null Values — In a Numeric Bucket, you can move all empty or null values to the bucket containing zero by selecting Treat empty values in the report as zeroes. If deselected, unbucketed values appear as a dash (-).

More limitations are available in Add a Bucket Column.