---

{ “title”: “UCASE/UPPER”, “language”: “en”, “description”: “The UCASE function (alias UPPER) converts all lowercase letters in a string to uppercase letters.” }

Description

The UCASE function (alias UPPER) converts all lowercase letters in a string to uppercase letters. This function supports Unicode character conversion and can correctly handle case conversion rules for various languages.

Syntax

UCASE(<str>)
UPPER(<str>)

Parameters

Parameter	Description
<str>	The string to convert to uppercase. Type: VARCHAR

Return Value

Returns VARCHAR type, representing the string converted to uppercase letters.

Conversion rules:

• Converts all lowercase letters in the string to corresponding uppercase letters
• Non-letter characters (numbers, symbols, spaces, etc.) remain unchanged
• Letters already in uppercase remain unchanged

Special cases:

• Returns NULL if parameter is NULL
• Returns empty string if string is empty
• Returns original string if there are no lowercase letters

Examples

1. Basic English letter conversion

SELECT UCASE('aBc123'), UPPER('aBc123');

+-----------------+-----------------+
| UCASE('aBc123') | UPPER('aBc123') |
+-----------------+-----------------+
| ABC123          | ABC123          |
+-----------------+-----------------+

2. Mixed character handling

SELECT UCASE('Hello World!'), UPPER('test@123');

+----------------------+------------------+
| UCASE('Hello World!') | UPPER('test@123') |
+----------------------+------------------+
| HELLO WORLD!         | TEST@123         |
+----------------------+------------------+

3. NULL value handling

SELECT UCASE(NULL), UPPER(NULL);

+-------------+-------------+
| UCASE(NULL) | UPPER(NULL) |
+-------------+-------------+
| NULL        | NULL        |
+-------------+-------------+

4. Empty string handling

SELECT UCASE(''), UPPER('');

+-----------+-----------+
| UCASE('') | UPPER('') |
+-----------+-----------+
|           |           |
+-----------+-----------+

5. Already uppercase string

SELECT UCASE('ALREADY UPPERCASE'), UPPER('ABC123');

+---------------------------+----------------+
| UCASE('ALREADY UPPERCASE') | UPPER('ABC123') |
+---------------------------+----------------+
| ALREADY UPPERCASE         | ABC123         |
+---------------------------+----------------+

6. Numbers and symbols

SELECT UCASE('123!@#$%'), UPPER('price: $99.99');

+-------------------+----------------------+
| UCASE('123!@#$%') | UPPER('price: $99.99') |
+-------------------+----------------------+
| 123!@#$%          | PRICE: $99.99        |
+-------------------+----------------------+

7. UTF-8 multi-byte characters

SELECT UCASE('ṭṛì test'), UPPER('ḍḍumai hello');

+--------------------+-----------------------+
| UCASE('ṭṛì test')  | UPPER('ḍḍumai hello') |
+--------------------+-----------------------+
| ṬṚÌ TEST           | ḌḌUMAI HELLO          |
+--------------------+-----------------------+

8. Cyrillic letters

SELECT UCASE('Кириллица'), UPPER('Бәйтерек');

+---------------------+-------------------+
| UCASE('Кириллица')  | UPPER('Бәйтерек') |
+---------------------+-------------------+
| КИРИЛЛИЦА           | БӘЙТЕРЕК          |
+---------------------+-------------------+

Keywords

UCASE, UPPER