The LOWER function

Use the LOWER function to replace every uppercase letter in a character string with a lowercase letter. The LOWER function accepts an argument of a character data type and returns a value of the same data type as the argument you specify.

The following query uses the LOWER function to convert any uppercase letters in a character string to lowercase letters.
Figure 1: Query
SELECT manu_code, LOWER(manu_code)
   FROM items
   WHERE order_num = 1018
Figure 2: Query result
manu_code   (expression)

PRC          prc
KAR          kar
PRC          prc
SMT          smt
HRO          hro