diff --git a/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/DeviceManagementService.java b/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/DeviceManagementService.java
index 8268fbaac66..01145b05ec1 100644
--- a/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/DeviceManagementService.java
+++ b/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/DeviceManagementService.java
@@ -271,7 +271,7 @@ public interface DeviceManagementService {
                     String ownership,
             @ApiParam(
                     name = "serialNumber",
-                    value = "The serialNumber of the device.",
+                    value = "The serial number of the device.",
                     required = false)
             @QueryParam("serialNumber")
                     String serialNumber,
diff --git a/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/DeviceManagementServiceImpl.java b/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/DeviceManagementServiceImpl.java
index 1a151bddf9f..7648a102b8d 100644
--- a/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/DeviceManagementServiceImpl.java
+++ b/components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/DeviceManagementServiceImpl.java
@@ -206,7 +206,7 @@ public class DeviceManagementServiceImpl implements DeviceManagementService {
                 RequestValidationUtil.validateOwnershipType(ownership);
                 request.setOwnership(ownership);
             }
-            if (serialNumber != null && !serialNumber.isEmpty()) {
+            if (StringUtils.isNotBlank(serialNumber)) {
                 request.setSerialNumber(serialNumber);
             }
             if (status != null && !status.isEmpty()) {
diff --git a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/GenericDeviceDAOImpl.java b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/GenericDeviceDAOImpl.java
index 22f06c3471e..eb3fa87f548 100644
--- a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/GenericDeviceDAOImpl.java
+++ b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/GenericDeviceDAOImpl.java
@@ -94,8 +94,11 @@ public class GenericDeviceDAOImpl extends AbstractDeviceDAOImpl {
 
             if (serial != null) {
                 sql = sql + "FROM DM_DEVICE d, DM_DEVICE_TYPE t, DM_DEVICE_INFO i " +
-                        "WHERE DEVICE_TYPE_ID = t.ID AND d.ID= i.DEVICE_ID " +
-                        "AND i.KEY_FIELD='serial' AND i.VALUE_FIELD = ? AND d.TENANT_ID = ? ";
+                        "WHERE DEVICE_TYPE_ID = t.ID " +
+                        "AND d.ID= i.DEVICE_ID " +
+                        "AND i.KEY_FIELD = 'serial' " +
+                        "AND i.VALUE_FIELD = ? " +
+                        "AND d.TENANT_ID = ? ";
                 isSerialProvided = true;
             } else {
                 sql = sql + "FROM DM_DEVICE d, DM_DEVICE_TYPE t WHERE DEVICE_TYPE_ID = t.ID AND d.TENANT_ID = ? ";
diff --git a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/OracleDeviceDAOImpl.java b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/OracleDeviceDAOImpl.java
index 044a681c9d0..4393a4546e5 100644
--- a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/OracleDeviceDAOImpl.java
+++ b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/OracleDeviceDAOImpl.java
@@ -94,8 +94,11 @@ public class OracleDeviceDAOImpl extends AbstractDeviceDAOImpl {
 
             if (serial != null) {
                 sql = sql + "FROM DM_DEVICE d, DM_DEVICE_TYPE t, DM_DEVICE_INFO i " +
-                        "WHERE DEVICE_TYPE_ID = t.ID AND d.ID= i.DEVICE_ID " +
-                        "AND i.KEY_FIELD='serial' AND i.VALUE_FIELD = ? AND d.TENANT_ID = ? ";
+                        "WHERE DEVICE_TYPE_ID = t.ID " +
+                        "AND d.ID= i.DEVICE_ID " +
+                        "AND i.KEY_FIELD = 'serial' " +
+                        "AND i.VALUE_FIELD = ? " +
+                        "AND d.TENANT_ID = ? ";
                 isSerialProvided = true;
             } else {
                 sql = sql + "FROM DM_DEVICE d, DM_DEVICE_TYPE t WHERE DEVICE_TYPE_ID = t.ID AND d.TENANT_ID = ? ";
diff --git a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/PostgreSQLDeviceDAOImpl.java b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/PostgreSQLDeviceDAOImpl.java
index 5bcbbea8bcc..66313603cb6 100644
--- a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/PostgreSQLDeviceDAOImpl.java
+++ b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/PostgreSQLDeviceDAOImpl.java
@@ -93,8 +93,11 @@ public class PostgreSQLDeviceDAOImpl extends AbstractDeviceDAOImpl {
 
             if (serial != null) {
                 sql = sql + "FROM DM_DEVICE d, DM_DEVICE_TYPE t, DM_DEVICE_INFO i " +
-                        "WHERE DEVICE_TYPE_ID = t.ID AND d.ID= i.DEVICE_ID " +
-                        "AND i.KEY_FIELD='serial' AND i.VALUE_FIELD = ? AND d.TENANT_ID = ? ";
+                        "WHERE DEVICE_TYPE_ID = t.ID " +
+                        "AND d.ID= i.DEVICE_ID " +
+                        "AND i.KEY_FIELD = 'serial' " +
+                        "AND i.VALUE_FIELD = ? " +
+                        "AND d.TENANT_ID = ? ";
                 isSerialProvided = true;
             } else {
                 sql = sql + "FROM DM_DEVICE d, DM_DEVICE_TYPE t WHERE DEVICE_TYPE_ID = t.ID AND d.TENANT_ID = ? ";
diff --git a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/SQLServerDeviceDAOImpl.java b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/SQLServerDeviceDAOImpl.java
index 95a69d36423..4e87d8ab61e 100644
--- a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/SQLServerDeviceDAOImpl.java
+++ b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/impl/device/SQLServerDeviceDAOImpl.java
@@ -95,8 +95,11 @@ public class SQLServerDeviceDAOImpl extends AbstractDeviceDAOImpl {
 
             if (serial != null) {
                 sql = sql + "FROM DM_DEVICE d, DM_DEVICE_TYPE t, DM_DEVICE_INFO i " +
-                        "WHERE DEVICE_TYPE_ID = t.ID AND d.ID= i.DEVICE_ID " +
-                        "AND i.KEY_FIELD='serial' AND i.VALUE_FIELD = ? AND d.TENANT_ID = ? ";
+                        "WHERE DEVICE_TYPE_ID = t.ID " +
+                        "AND d.ID= i.DEVICE_ID " +
+                        "AND i.KEY_FIELD = 'serial' " +
+                        "AND i.VALUE_FIELD = ? " +
+                        "AND d.TENANT_ID = ? ";
                 isSerialProvided = true;
             } else {
                 sql = sql + "FROM DM_DEVICE d, DM_DEVICE_TYPE t WHERE DEVICE_TYPE_ID = t.ID AND d.TENANT_ID = ? ";