ORA-01722: invalid number
Oracle tried to convert a string to a number and failed.
Seen on:
SQL
Meaning
Implicit conversions from comparing VARCHAR2 with numbers, or NLS decimal settings (comma vs dot).
Common causes
- Comparing varchar columns to numeric literals
- Non-numeric data in a column treated as numeric
- NLS_NUMERIC_CHARACTERS mismatch
⚡ Quick fix
- Compare with string literals or convert explicitly
- Use VALIDATE_CONVERSION/TO_NUMBER … DEFAULT NULL ON CONVERSION ERROR (12.2+)
Detailed fix by platform
SQL
SELECT TO_NUMBER(code DEFAULT NULL ON CONVERSION ERROR) FROM items;
How to diagnose
- Expression — Where is the implicit conversion?
- Recent change — Did it start after a deploy, upgrade, or configuration change? Compare with the last working version.
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Last updated 2 Oct 2026