How to Fix PostgreSQL Error: Numeric Field Overflow

The "Numeric field overflow" error occurs when a value exceeds the defined precision or scale of a NUMERIC/DECIMAL column.

Impact

Prevents insertion or calculation of values that don't fit within the defined numeric precision and scale constraints.

Common Causes

1. NUMERIC(p,s) precision too small
2. Calculation results exceeding precision
3. Too many decimal places for scale
4. Conversion from larger to smaller precision

Troubleshooting and Resolution Steps

1. Understand NUMERIC(precision, scale):

   -- NUMERIC(10,2) means:
   -- Total 10 digits, 2 after decimal
   -- Range: -99999999.99 to 99999999.99
   
   -- Check column definition
   \d table_name
   

2. Increase precision:

   -- Increase precision and scale
   ALTER TABLE products
   ALTER COLUMN price TYPE NUMERIC(12,4);
   
   -- For very large numbers
   ALTER TABLE accounts
   ALTER COLUMN balance TYPE NUMERIC(20,2);
   

3. Use unlimited NUMERIC:

   -- NUMERIC without precision is unlimited
   ALTER TABLE calculations
   ALTER COLUMN result TYPE NUMERIC;
   

Additional Information

• NUMERIC(p,s): p=total digits, s=decimal places
• Without precision, NUMERIC can store very large values
• Use appropriate precision for your data range
• Financial calculations should use NUMERIC, not FLOAT

Frequently Asked Questions

Q: What's the maximum precision for NUMERIC?
A: Up to 131072 digits before decimal, 16383 after (implementation-dependent).

Q: Should I always specify precision?
A: Specify for known constraints. Use unlimited NUMERIC for variable precision needs.

Q: What's the difference between NUMERIC and DECIMAL?
A: They're equivalent in PostgreSQL. NUMERIC is preferred for clarity.