diff --git a/src/main/java/net/sf/jsqlparser/expression/StringValue.java b/src/main/java/net/sf/jsqlparser/expression/StringValue.java
index 3f7ebbca3..c5ef705af 100644
--- a/src/main/java/net/sf/jsqlparser/expression/StringValue.java
+++ b/src/main/java/net/sf/jsqlparser/expression/StringValue.java
@@ -52,7 +52,7 @@ public StringValue(String escapedValue) {
 
         if (escapedValue.length() > 2) {
             for(String p : ALLOWED_PREFIXES) {
-                if(escapedValue.length() > p.length() && escapedValue.substring(0, p.length()).toUpperCase().equals(p) && escapedValue.charAt(p.length())=='\'') {
+                if(escapedValue.length() > p.length() && escapedValue.substring(0, p.length()).equalsIgnoreCase(p) && escapedValue.charAt(p.length())=='\'') {
                     this.prefix = p;
                     value = escapedValue.substring(p.length() + 1, escapedValue.length() - 1);
                     return;