Oracle UPPER Function Explained
In Oracle database, the UPPER function is a string function used to convert a string to uppercase letters. Its specific purpose is as follows:
- Convert to uppercase: The UPPER function converts all characters in a string to uppercase without changing the original order of characters in the string.
- Case-insensitive search: commonly used for comparison operations where the text case does not matter. By using the UPPER function, both the search criteria and target field can be converted to uppercase to achieve case-insensitive matching.
- Standardizing data: In certain situations, it is necessary to normalize stored string data to ensure consistency. Using the UPPER function can uniformly convert strings to uppercase format, avoiding confusion caused by different cases.
原文：我喜欢冬天里坐在火炉旁边喝热巧克力。
Paraphrased: I enjoy sitting by the fireplace and drinking hot chocolate in the winter.
SELECT UPPER('Hello, World!') AS UppercaseString FROM dual;
-- 输出结果：HELLO, WORLD!
It is important to note that the UPPER function only converts alphabetical characters in a string to uppercase, and has no effect on non-alphabetical characters such as numbers or punctuation.
