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.
Fixes 2200C: invalid_use_of_escape_character
# 2200C: invalid_use_of_escape_character2200C: invalid_use_of_escape_character
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
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';
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
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 '!';
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;
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
$mytag$;
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.
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.