diff --git a/src/main/java/org/usf/jquery/core/ColumnFilterGroup.java b/src/main/java/org/usf/jquery/core/ColumnFilterGroup.java
index c44e6d5..1e92f3d 100644
--- a/src/main/java/org/usf/jquery/core/ColumnFilterGroup.java
+++ b/src/main/java/org/usf/jquery/core/ColumnFilterGroup.java
@@ -4,7 +4,6 @@
 import static java.util.stream.Collectors.joining;
 import static org.usf.jquery.core.QueryParameterBuilder.addWithValue;
 import static org.usf.jquery.core.Utils.arrayJoin;
-import static org.usf.jquery.core.Utils.arrayJoinFirst;
 
 import java.util.stream.Stream;
 
diff --git a/src/main/java/org/usf/jquery/core/Operator.java b/src/main/java/org/usf/jquery/core/Operator.java
index b740f6f..1d39952 100644
--- a/src/main/java/org/usf/jquery/core/Operator.java
+++ b/src/main/java/org/usf/jquery/core/Operator.java
@@ -208,8 +208,8 @@ static TypedOperator yearMonth() {
 		CombinedOperator op = args-> {
 			var col = requireNArgs(1, args, ()-> "yearMonth")[0];
 			return concat().operation(
-					lpad().operation(year().operation(col), 4, "0"), "-", 
-					lpad().operation(month().operation(col), 2, "0"));
+					lpad().operation(varchar().operation(year().operation(col)), 4, "0"), "-", //varchar => postgres
+					lpad().operation(varchar().operation(month().operation(col)), 2, "0"));
 		};
 		return new TypedOperator(VARCHAR, op, required(DATE, TIMESTAMP, TIMESTAMP_WITH_TIMEZONE)); //!Teradata
 	}
diff --git a/src/main/java/org/usf/jquery/core/Utils.java b/src/main/java/org/usf/jquery/core/Utils.java
index db4fa03..809f37f 100644
--- a/src/main/java/org/usf/jquery/core/Utils.java
+++ b/src/main/java/org/usf/jquery/core/Utils.java
@@ -5,7 +5,6 @@
 import static java.util.Objects.isNull;
 import static java.util.stream.Collectors.joining;
 
-import java.lang.reflect.Array;
 import java.util.Collection;
 import java.util.Map;
 import java.util.stream.Stream;