diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/base/RuleCollections.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/base/RuleCollections.java
index d5169c7..783fbaa 100644
--- a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/base/RuleCollections.java
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/base/RuleCollections.java
@@ -20,6 +20,7 @@
 
 import edu.uci.ics.asterix.optimizer.rules.AsterixInlineVariablesRule;
 import edu.uci.ics.asterix.optimizer.rules.ByNameToByIndexFieldAccessRule;
+import edu.uci.ics.asterix.optimizer.rules.CheckFilterExpressionTypeRule;
 import edu.uci.ics.asterix.optimizer.rules.ConstantFoldingRule;
 import edu.uci.ics.asterix.optimizer.rules.CountVarToCountOneRule;
 import edu.uci.ics.asterix.optimizer.rules.ExtractDistinctByExpressionsRule;
@@ -103,6 +104,7 @@
         List<IAlgebraicRewriteRule> typeInfer = new LinkedList<IAlgebraicRewriteRule>();
         typeInfer.add(new InlineUnnestFunctionRule());
         typeInfer.add(new InferTypesRule());
+        typeInfer.add(new CheckFilterExpressionTypeRule());
         return typeInfer;
     }
 
diff --git a/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/CheckFilterExpressionTypeRule.java b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/CheckFilterExpressionTypeRule.java
new file mode 100644
index 0000000..aa57ab9
--- /dev/null
+++ b/asterix-algebra/src/main/java/edu/uci/ics/asterix/optimizer/rules/CheckFilterExpressionTypeRule.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright 2009-2013 by The Regents of the University of California
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * you may obtain a copy of the License from
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package edu.uci.ics.asterix.optimizer.rules;
+
+import org.apache.commons.lang3.mutable.Mutable;
+
+import edu.uci.ics.asterix.om.types.ATypeTag;
+import edu.uci.ics.asterix.om.types.AUnionType;
+import edu.uci.ics.asterix.om.types.IAType;
+import edu.uci.ics.asterix.om.util.NonTaggedFormatUtil;
+import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalExpression;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.ILogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.IOptimizationContext;
+import edu.uci.ics.hyracks.algebricks.core.algebra.base.LogicalOperatorTag;
+import edu.uci.ics.hyracks.algebricks.core.algebra.expressions.IVariableTypeEnvironment;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator;
+import edu.uci.ics.hyracks.algebricks.core.algebra.operators.logical.SelectOperator;
+import edu.uci.ics.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;
+
+/**
+ * This rule is to check if all the filter expression are of the boolean type or a possible (determined
+ * at the runtime) boolean type.
+ * If that is not the case, an exception should be thrown.
+ * 
+ * @author yingyib
+ */
+public class CheckFilterExpressionTypeRule implements IAlgebraicRewriteRule {
+
+    @Override
+    public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context) throws AlgebricksException {
+        return false;
+    }
+
+    @Override
+    public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context)
+            throws AlgebricksException {
+        AbstractLogicalOperator op = (AbstractLogicalOperator) opRef.getValue();
+        if (op.getOperatorTag() != LogicalOperatorTag.SELECT) {
+            return false;
+        }
+        SelectOperator select = (SelectOperator) op;
+        ILogicalExpression condition = select.getCondition().getValue();
+        IVariableTypeEnvironment env = select.computeOutputTypeEnvironment(context);
+        IAType condType = (IAType) env.getType(condition);
+        if (condType.getTypeTag() != ATypeTag.BOOLEAN && condType.getTypeTag() != ATypeTag.ANY
+                && !isPossibleBoolean(condType)) {
+            throw new AlgebricksException("The select condition " + condition.toString()
+                    + " should be of the boolean type.");
+        }
+        return false;
+    }
+
+    /**
+     * Check if the type is optional boolean or not
+     * 
+     * @param type
+     * @return true if it is; false otherwise.
+     */
+    private boolean isPossibleBoolean(IAType type) {
+        while (type.getTypeTag() == ATypeTag.UNION && NonTaggedFormatUtil.isOptionalField((AUnionType) type)) {
+            type = ((AUnionType) type).getUnionList().get(NonTaggedFormatUtil.OPTIONAL_TYPE_INDEX_IN_UNION_LIST);
+            if (type.getTypeTag() == ATypeTag.BOOLEAN || type.getTypeTag() == ATypeTag.ANY) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+}
diff --git a/asterix-app/src/test/resources/runtimets/queries/user-defined-functions/udf27/udf27.3.query.aql b/asterix-app/src/test/resources/runtimets/queries/user-defined-functions/udf27/udf27.3.query.aql
index 50a1cb2..fd383cf 100644
--- a/asterix-app/src/test/resources/runtimets/queries/user-defined-functions/udf27/udf27.3.query.aql
+++ b/asterix-app/src/test/resources/runtimets/queries/user-defined-functions/udf27/udf27.3.query.aql
@@ -10,4 +10,4 @@
 use dataverse test;
 
 let $a := true
-return some $i in [100,200] satisfies test.f1()
+return some $i in [100,200] satisfies $i<test.f1()