diff --git a/system/database/drivers/cubrid/cubrid_driver.php b/system/database/drivers/cubrid/cubrid_driver.php
index 74b8d99..4021179 100644
--- a/system/database/drivers/cubrid/cubrid_driver.php
+++ b/system/database/drivers/cubrid/cubrid_driver.php
@@ -318,7 +318,7 @@
 
 		if ($prefix_limit !== FALSE && $this->dbprefix !== '')
 		{
-			$sql ." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
+			return $sql." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
 		}
 
 		return $sql;
diff --git a/system/database/drivers/ibase/ibase_driver.php b/system/database/drivers/ibase/ibase_driver.php
index fa04ad5..529c320 100644
--- a/system/database/drivers/ibase/ibase_driver.php
+++ b/system/database/drivers/ibase/ibase_driver.php
@@ -234,7 +234,7 @@
 
 		if ($prefix_limit !== FALSE && $this->dbprefix !== '')
 		{
-			$sql .' AND TRIM("RDB$RELATION_NAME") AS TABLE_NAME LIKE \''.$this->escape_like_str($this->dbprefix)."%' "
+			return $sql.' AND TRIM("RDB$RELATION_NAME") AS TABLE_NAME LIKE \''.$this->escape_like_str($this->dbprefix)."%' "
 				.sprintf($this->_like_escape_str, $this->_like_escape_chr);
 		}
 
diff --git a/system/database/drivers/mysql/mysql_driver.php b/system/database/drivers/mysql/mysql_driver.php
index d571c45..f8e9b6d 100644
--- a/system/database/drivers/mysql/mysql_driver.php
+++ b/system/database/drivers/mysql/mysql_driver.php
@@ -390,7 +390,7 @@
 
 		if ($prefix_limit !== FALSE && $this->dbprefix !== '')
 		{
-			$sql ." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
+			return $sql." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
 		}
 
 		return $sql;
diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index 82c0434..22a8ba6 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_driver.php
@@ -375,7 +375,7 @@
 
 		if ($prefix_limit !== FALSE && $this->dbprefix !== '')
 		{
-			$sql ." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
+			return $sql." LIKE '".$this->escape_like_str($this->dbprefix)."%'";
 		}
 
 		return $sql;
diff --git a/system/database/drivers/oci8/oci8_driver.php b/system/database/drivers/oci8/oci8_driver.php
index ccd6419..b87b411 100644
--- a/system/database/drivers/oci8/oci8_driver.php
+++ b/system/database/drivers/oci8/oci8_driver.php
@@ -494,7 +494,7 @@
 
 		if ($prefix_limit !== FALSE && $this->dbprefix !== '')
 		{
-			$sql .' WHERE "TABLE_NAME" LIKE \''.$this->escape_like_str($this->dbprefix)."%' "
+			return $sql.' WHERE "TABLE_NAME" LIKE \''.$this->escape_like_str($this->dbprefix)."%' "
 				.sprintf($this->_like_escape_str, $this->_like_escape_chr);
 		}
 
diff --git a/system/database/drivers/odbc/odbc_driver.php b/system/database/drivers/odbc/odbc_driver.php
index 559617a..f5d77a1 100644
--- a/system/database/drivers/odbc/odbc_driver.php
+++ b/system/database/drivers/odbc/odbc_driver.php
@@ -255,7 +255,7 @@
 
 		if ($prefix_limit !== FALSE && $this->dbprefix !== '')
 		{
-			$sql ." AND table_name LIKE '".$this->escape_like_str($this->dbprefix)."%' "
+			return $sql." AND table_name LIKE '".$this->escape_like_str($this->dbprefix)."%' "
 				.sprintf($this->_like_escape_str, $this->_like_escape_chr);
 		}
 
diff --git a/system/database/drivers/postgre/postgre_driver.php b/system/database/drivers/postgre/postgre_driver.php
index 8f72199..3f3e3f0 100644
--- a/system/database/drivers/postgre/postgre_driver.php
+++ b/system/database/drivers/postgre/postgre_driver.php
@@ -430,7 +430,7 @@
 
 		if ($prefix_limit !== FALSE && $this->dbprefix !== '')
 		{
-			$sql .' AND "table_name" LIKE \''
+			return $sql.' AND "table_name" LIKE \''
 				.$this->escape_like_str($this->dbprefix)."%' "
 				.sprintf($this->_like_escape_str, $this->_like_escape_chr);
 		}
diff --git a/system/database/drivers/sqlite/sqlite_driver.php b/system/database/drivers/sqlite/sqlite_driver.php
index 42dd9a7..9d9caa0 100644
--- a/system/database/drivers/sqlite/sqlite_driver.php
+++ b/system/database/drivers/sqlite/sqlite_driver.php
@@ -233,7 +233,7 @@
 
 		if ($prefix_limit !== FALSE && $this->dbprefix != '')
 		{
-			$sql ." AND 'name' LIKE '".$this->escape_like_str($this->dbprefix)."%' ".sprintf($this->_like_escape_str, $this->_like_escape_chr);
+			return $sql." AND 'name' LIKE '".$this->escape_like_str($this->dbprefix)."%' ".sprintf($this->_like_escape_str, $this->_like_escape_chr);
 		}
 
 		return $sql;