How to create an all uppercase string in MySQL

The MySQL UPPER and UCASE functions are used to transform a string of characters into its all uppercase version.

You need to provide the string you wish to transform as the argument to the functions as shown below:

UPPER(str)

-- OR

UCASE(str)

For example, the following query transforms england as ENGLAND:

SELECT UPPER("england");

-- +------------------+
-- | UPPER("england") |
-- +------------------+
-- | ENGLAND          |
-- +------------------+

The function can only transforms one string at a time, so passing multiple strings will result in an error:

SELECT UPPER("england", "wales");

-- ERROR 1582 (42000): Incorrect parameter count in the call to native function 'UPPER'

To transform multiple strings, you need to call the function for each string separated by a comma:

SELECT UPPER("england"), UPPER("wales");

-- +------------------+----------------+
-- | UPPER("england") | UPPER("wales") |
-- +------------------+----------------+
-- | ENGLAND          | WALES          |
-- +------------------+----------------+

Finally, you can also pass a column name as the argument to the UPPER or UCASE functions to run the function on each column value.

Suppose you have a table called countries with the following data:

+----+------------------+
| id | name             |
+----+------------------+
|  1 | england          |
|  2 | wales            |
|  3 | northern ireland |
|  4 | scotland         |
+----+------------------+

You can pass the name column into the UPPER function as shown below:

SELECT UPPER(name) FROM countries;

The returned result set will be as follows:

+------------------+
| UPPER(name)      |
+------------------+
| ENGLAND          |
| WALES            |
| NORTHERN IRELAND |
| SCOTLAND         |
+------------------+

And that’s how you transform a string of characters into its uppercase version in MySQL.

If you want to do the opposite and transform a string into its lowercase version, then you can use the MySQL LOWER function and its alias LCASE function.

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