Remove Spaces from String in Oracle

In Oracle, you can utilize the REPLACE() function to remove spaces from a string. The specific usage is as follows:

SELECT REPLACE('Hello World', ' ', '') FROM dual;

In the above code, the first parameter of the REPLACE() function is the string to be processed, the second parameter is the character to be replaced (in this case, a space), and the third parameter is the character to replace it with (in this case, an empty string). By replacing the spaces with an empty string, you can remove the spaces from the string.

To remove all spaces in a string, you can use the REGEXP_REPLACE() function.

SELECT REGEXP_REPLACE('Hello    World', '[[:space:]]', '') FROM dual;

In the above code, the first parameter of the REGEXP_REPLACE() function is the string to be processed, the second parameter [[:space:]] is a regular expression used to match all whitespace characters, and the third parameter is the character to replace with (in this case, an empty string). By replacing all matched whitespace characters with an empty string, all spaces in the string can be removed.