LCASE/LOWER
Description
The LCASE function (alias LOWER) converts all uppercase letters in a string to lowercase.
Syntax
LCASE(<str>)
LOWER(<str>)
Parameters
| Parameter | Description |
|---|---|
<str> | The string to convert to lowercase. Type: VARCHAR |
Return Value
Returns VARCHAR type, representing the string after conversion to lowercase.
Conversion rules:
- Converts all uppercase letters in the string to their corresponding lowercase letters
- Non-letter characters (numbers, symbols, spaces, etc.) remain unchanged
- Letters that are already lowercase remain unchanged
Special cases:
- If parameter is NULL, returns NULL
- If string is empty, returns empty string
- If string contains no uppercase letters, returns original string
Examples
- Basic English letter conversion
SELECT LOWER('AbC123'), LCASE('AbC123');
+-----------------+-----------------+
| LOWER('AbC123') | LCASE('AbC123') |
+-----------------+-----------------+
| abc123 | abc123 |
+-----------------+-----------------+
- Mixed character handling
SELECT LOWER('Hello World!'), LCASE('TEST@123');
+----------------------+------------------+
| LOWER('Hello World!') | LCASE('TEST@123') |
+----------------------+------------------+
| hello world! | test@123 |
+----------------------+------------------+
- NULL value handling
SELECT LOWER(NULL), LCASE(NULL);
+-------------+-------------+
| LOWER(NULL) | LCASE(NULL) |
+-------------+-------------+
| NULL | NULL |
+-------------+-------------+
- Empty string
SELECT LOWER(''), LCASE('');
+-----------+-----------+
| LOWER('') | LCASE('') |
+-----------+-----------+
| | |
+-----------+-----------+
- String already lowercase or numeric-only
SELECT LOWER('already lowercase'), LCASE('abc123');
+----------------------------+-----------------+
| LOWER('already lowercase') | LCASE('abc123') |
+----------------------------+-----------------+
| already lowercase | abc123 |
+----------------------------+-----------------+
- Non-alphabetic characters are passed through unchanged
SELECT LOWER('123!@#$%'), LCASE('PRICE: $99.99');
+-------------------+------------------------+
| LOWER('123!@#$%') | LCASE('PRICE: $99.99') |
+-------------------+------------------------+
| 123!@#$% | price: $99.99 |
+-------------------+------------------------+
- UTF-8 multi-byte case folding
SELECT LOWER('ṬṚÌ TEST'), LCASE('ḌḌUMAI HELLO');
+------------------------+---------------------------+
| LOWER('ṬṚÌ TEST') | LCASE('ḌḌUMAI HELLO') |
+------------------------+---------------------------+
| ṭṛì test | ḍḍumai hello |
+------------------------+---------------------------+
