diff --git a/jOOQ/src/main/java/org/jooq/impl/Greatest.java b/jOOQ/src/main/java/org/jooq/impl/Greatest.java
index 64be8239fa..3bac02b03d 100644
--- a/jOOQ/src/main/java/org/jooq/impl/Greatest.java
+++ b/jOOQ/src/main/java/org/jooq/impl/Greatest.java
@@ -71,6 +71,7 @@ class Greatest<T> extends AbstractFunction<T> {
 
             case ASE:
             case DERBY:
+            case FIREBIRD:
             case SQLSERVER:
             case SYBASE: {
                 Field<T> first = (Field<T>) getArguments()[0];
diff --git a/jOOQ/src/main/java/org/jooq/impl/Least.java b/jOOQ/src/main/java/org/jooq/impl/Least.java
index 963fc4244d..9d7f720150 100644
--- a/jOOQ/src/main/java/org/jooq/impl/Least.java
+++ b/jOOQ/src/main/java/org/jooq/impl/Least.java
@@ -70,6 +70,7 @@ class Least<T> extends AbstractFunction<T> {
 
             case ASE:
             case DERBY:
+            case FIREBIRD:
             case SQLSERVER:
             case SYBASE: {
                 Field<T> first = (Field<T>) getArguments()[0];