How to fix 2200C: invalid_use_of_escape_character in PostgreSQL

PostgreSQLINTERMEDIATEMEDIUMUpdated Dec 22, 2025· 118 views

PostgreSQL error 2200C occurs when escape characters are used incorrectly in SQL statements. Common causes include using backslash escapes without the E prefix or invalid Unicode escape sequences.

Quick fix

Fixes 2200C: invalid_use_of_escape_character

  1. Check if escape characters are needed
  2. Use E prefix for backslash escapes
  3. Fix Unicode escape strings
  4. Check standard_conforming_strings
  5. Use dollar-quoting
postgresql — error
# 2200C: invalid_use_of_escape_character
2200C: invalid_use_of_escape_character

What this error means

The "invalid_use_of_escape_character" error (SQLSTATE 2200C) is a data exception error that occurs when PostgreSQL encounters escape characters being used in contexts where they are not allowed or are syntactically incorrect. Escape characters in PostgreSQL have specific purposes: backslashes introduce escape sequences in E-prefixed strings, and ampersands are used for Unicode escapes in U& strings. This error typically happens when: 1. Using backslash escapes in regular string literals without the E prefix 2. Using invalid escape sequences that PostgreSQL does not recognize 3. Incorrect Unicode escape syntax in U& strings 4. Ambiguous use of the & operator near Unicode escape strings

Typical symptoms

  • SQL queries fail with error message "2200C: invalid_use_of_escape_character"
  • Backslash escape sequences do not work as expected
  • Unicode escape strings fail to parse
  • Queries that worked in older PostgreSQL versions now fail
  • Application code with escape characters throws database errors

Common causes

  1. Using backslash escapes in regular strings without E prefix
  2. Invalid escape sequences in E strings
  3. Incorrect Unicode escape syntax
  4. standard_conforming_strings setting is enabled (default)
  5. Ambiguous & operator usage
  6. Migrating from older PostgreSQL versions

How to fix "2200C: invalid_use_of_escape_character"

1Check if escape characters are needed

Determine if you actually need escape characters. For literal backslashes or ampersands, you may not need escape sequences.

Example for literal backslash:
SELECT 'C:\\\\Users\\\\name';

Example for literal ampersand:
SELECT 'AT&T';

2Use E prefix for backslash escapes

If you need backslash escapes, use E prefix:

Wrong:
SELECT 'line1\\\\nline2';

Correct:
SELECT E'line1\\\\nline2';

Valid escape sequences include: \\\\b, \\\\f, \\\\n, \\\\r, \\\\t, \\\\o, \\\\x, \\\\u, \\\\U

3Fix Unicode escape strings

For Unicode escapes, ensure proper syntax:

4-digit hex:
SELECT U&'d\\\\0061t\\\\0061';

6-digit with + sign:
SELECT U&'d\\\\+000061t\\\\+000061';

Custom escape:
SELECT U&'d!0061t!+000061' UESCAPE '!';

4Check standard_conforming_strings

Check the setting:
SHOW standard_conforming_strings;

If 'on', use E prefix. For old code migration:

Option 1: Update queries
SELECT E'line1\\\\nline2';

Option 2: Temporary change (not for production)
SET standard_conforming_strings = off;
-- Run query
SET standard_conforming_strings = on;

5Use dollar-quoting

For complex strings, use dollar-quoting:

Instead of:
SELECT E'Complex string with quotes';

Use:
SELECT $$
Complex string with quotes
$$;

Or with custom tag:
SELECT $mytag$
Complex string
$mytag$;

6Test your fixes

Test queries after changes:

Test backslash escapes:
SELECT E'Test\\\\nNew\\\\tLine';

Test Unicode:
SELECT U&'Hello \\\\0061\\\\0062\\\\0063';

Use parameterized queries in application code.

Advanced notes

Configuration Notes:

1. Historical: PostgreSQL 8.2 had standard_conforming_strings off by default.
2. Warning: escape_string_warning setting warns about backslashes in regular strings.
3. Encoding: Client encoding affects escape sequence interpretation.
4. Security: Use parameterized queries to prevent SQL injection.
5. Migration: Audit string literals when migrating from older versions.

Frequently asked questions

What does "2200C: invalid_use_of_escape_character" mean?
The "invalid_use_of_escape_character" error (SQLSTATE 2200C) is a data exception error that occurs when PostgreSQL encounters escape characters being used in contexts where they are not allowed or are syntactically incorrect. Escape characters in PostgreSQL have specific purposes: backslashes introduce escape sequences in E-prefixed strings, and ampersands are used for Unicode escapes in U& strings. This error typically happens when: 1.
How do I fix "2200C: invalid_use_of_escape_character"?
PostgreSQL error 2200C occurs when escape characters are used incorrectly in SQL statements. Common causes include using backslash escapes without the E prefix or invalid Unicode escape sequences.
What causes "2200C: invalid_use_of_escape_character"?
Using backslash escapes in regular strings without E prefix Invalid escape sequences in E strings Incorrect Unicode escape syntax
Is the "2200C: invalid_use_of_escape_character" error serious?
It is a medium-severity error — more of a blocker than a risk. The steps above resolve it.

Official resources & further reading