lower bound cannot equal upper bound

Symptoms

A statement failed with SQLSTATE 2201G (invalid_argument_for_width_bucket_function), reported at severity ERROR. This is a Data Exception condition: PostgreSQL emits the message lower bound cannot equal upper bound.

• The client receives SQLSTATE 2201G (invalid argument for width bucket function).
• The operation is rejected at ERROR level; the statement does not complete.

What the server log shows

ERROR:  lower bound cannot equal upper bound

Why PostgreSQL raises this

Class 22 (Data Exception) is raised at run time when a value cannot be represented, converted, or processed by the requested type or function — bad input syntax, out-of-range values, or invalid arguments.

As described in PostgreSQL’s Chapter 8 Data Types and Appendix A (PostgreSQL Error Codes), SQLSTATE 2201G carries the condition name invalid_argument_for_width_bucket_function in class Data Exception. (Paraphrased — see the linked reference for the exact wording.)

Common causes

• A literal or parameter does not match the target type’s input format.
• A value exceeds the range or length the type allows.
• A function received an argument outside its valid domain.
• An encoding, cast, or format conversion failed.

How to fix it

1. Validate and sanitize the input value before sending it.
2. Cast explicitly to the intended type and confirm the format.
3. Widen the column/type or clamp the value to the supported range.
4. Reproduce with the exact literal to see which value is rejected.

Version applicability

This message is present in PostgreSQL 15, 16, 17, 18 and 19.

Related & next steps

• SQLSTATE 2201G — Invalid Argument For Width Bucket Function (full reference)
• PostgreSQL error code index

Reference: PostgreSQL Chapter 8 Data Types.