Better approach is to use lowercase on WhereDatePart method

Author: andrevlins

QueryBuilder/Base.Where.cs

@@ -581,7 +581,7 @@ public Q WhereDatePart(string part, string column, string op, object value)
                 Operator = op,
                 Column = column,
                 Value = value,
-                Part = part,
+                Part = part?.ToLowerInvariant(),
                 IsOr = GetOr(),
                 IsNot = GetNot(),
             });

QueryBuilder/Compilers/OracleCompiler.cs

@@ -108,7 +108,7 @@ protected override string CompileBasicDateCondition(SqlResult ctx, BasicDateCond
 
             var isDateTime = (condition.Value is DateTime dt);
 
-            switch (condition.Part?.ToLowerInvariant())
+            switch (condition.Part)
             {
                 case "date": // assume YY-MM-DD format
                     if (isDateTime)