In order to convert character or string columns in SQL to UPPER or LOWER case we need to know the proper SQL functions. Easily enough, the ANSI-SQL functions for providing upper and lower-case values are UPPER() and LOWER().
Upper-Case SQL Syntax
SELECT UPPER(‘<column_name>‘) AS ColumnName FROM Table;
Lower-Case SQL Syntax
SELECT LOWER(‘<column_name>‘) AS ColumnName FROM Table;
These functions can be used across most databases as a result of being ANSI-Standard SQL. As a result, these functions can also be used in conjunction with other functions. Just be sure for every open parentheses to include closed parentheses.
Practical Examples of Changing to Upper/Lower-Case
We can look at practical examples to view how we can actually use and write the SQL. We can also use these functions on multiple columns as shown in the example below.
We can see the resulting output with both columns with upper-case letters.
Final Thoughts & Camel-Case
Using UPPER and LOWER functions in SQL are fairly straight-forward. However, there are also other ways to compliment these functions. We can use functions like SUBSTRING() or SUBSTR() to upper-case the first letter and lower-case the rest. Combining substring and the upper/lower functions will accomplish most case sensitivity cases in SQL. Some databases include their own functions to accomplish other case sensitivity options so refer to those specific database documents.