Error
Error Code:
3697
MySQL Error 3697: Invalid Regex Character Range
Description
This error indicates that a regular expression used in a MySQL query contains an improperly defined character range. Specifically, within a `[x-y]` range, the starting character `x` has a higher collation or ASCII value than the ending character `y`, making the range illogical and invalid. This prevents the regular expression from being parsed correctly.
Error Message
The regular expression contains an [x-y] character range where x comes after y.
Known Causes
3 known causesIncorrect Character Range Order
A simple typographical error where the start and end characters within a `[x-y]` range are accidentally swapped (e.g., `[z-a]` instead of `[a-z]`).
Misunderstanding Collation or ASCII Values
Attempting to define a range like `[9-0]` or `[Z-A]` without realizing that their underlying ASCII or collation order makes these ranges inverted and invalid.
Programmatic Regex Generation Issue
If the regular expression is constructed dynamically by an application, a bug in the generation logic might inadvertently produce an invalid character range.
Solutions
3 solutions available1. Correct Reversed Character Ranges easy
Identify and reverse any character ranges in your regex where the start character comes after the end character.
1
Examine the regular expression causing the error. Look for patterns like `[z-a]` or `[9-0]` within your regex string.
2
Reorder the characters within the square brackets so that the starting character precedes the ending character. For example, change `[z-a]` to `[a-z]` and `[9-0]` to `[0-9]`.
Example: `REGEXP '[z-a]'` should become `REGEXP '[a-z]'.`3
Update your SQL query or application code with the corrected regular expression.
2. Simplify Regex by Removing Invalid Ranges easy
If a reversed character range is not essential, remove it entirely from the regex.
1
Review the regular expression and determine if the specific character range causing the error is critical for matching. If the intent was to match individual characters rather than a range, consider listing them explicitly.
2
If the range is not crucial, remove it. For example, if `[z-a]` was accidentally included and the intent was to match 'z' and 'a' separately, you can either remove `[z-a]` if neither is needed, or change it to `[za]`.
Example: `REGEXP 'some_pattern[z-a]'` might be simplified to `REGEXP 'some_pattern'` if `[z-a]` is not needed, or `REGEXP 'some_pattern[za]'` if 'z' and 'a' should be matched individually.3
Apply the modified regex to your SQL query or application code.
3. Utilize Character Sets for Clearer Matching medium
Replace problematic character ranges with explicit character sets for better readability and correctness.
1
Identify the intended characters within the invalid range. For instance, if you have `[z-a]`, the intended characters might be 'a', 'b', 'c', ..., 'z'.
2
Create a new character set that explicitly lists all the desired characters in ascending order. For `[z-a]`, this would be `[abcdefghijklmnopqrstuvwxyz]`.
3
Substitute the original invalid range with the newly created explicit character set in your regular expression.
Example: Replace `REGEXP '[z-a]'` with `REGEXP '[abcdefghijklmnopqrstuvwxyz]'.`4
Test the updated regex thoroughly to ensure it matches the intended patterns.