Merge changes from develop

20 files changed, 100 insertions, 240 deletions

diff --git a/system/database/drivers/cubrid/cubrid_driver.php b/system/database/drivers/cubrid/cubrid_driver.php
index 28724e0e8..01d0ee39e 100644
--- a/system/database/drivers/cubrid/cubrid_driver.php
+++ b/system/database/drivers/cubrid/cubrid_driver.php
@@ -429,6 +429,26 @@ class CI_DB_cubrid_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Close DB Connection
 	 *
 	 * @return	void
diff --git a/system/database/drivers/ibase/ibase_driver.php b/system/database/drivers/ibase/ibase_driver.php
index f7811bf46..ab1d1b88d 100644
--- a/system/database/drivers/ibase/ibase_driver.php
+++ b/system/database/drivers/ibase/ibase_driver.php
@@ -302,22 +302,6 @@ class CI_DB_ibase_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This public function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/mssql/mssql_driver.php b/system/database/drivers/mssql/mssql_driver.php
index b4a1af7ba..a62ea94b3 100644
--- a/system/database/drivers/mssql/mssql_driver.php
+++ b/system/database/drivers/mssql/mssql_driver.php
@@ -362,22 +362,6 @@ class CI_DB_mssql_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/mysql/mysql_driver.php b/system/database/drivers/mysql/mysql_driver.php
index 6b4d84dfb..7262591ee 100644
--- a/system/database/drivers/mysql/mysql_driver.php
+++ b/system/database/drivers/mysql/mysql_driver.php
@@ -465,6 +465,26 @@ class CI_DB_mysql_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Close DB Connection
 	 *
 	 * @return	void
diff --git a/system/database/drivers/mysqli/mysqli_driver.php b/system/database/drivers/mysqli/mysqli_driver.php
index 14949ecda..b5a1e26ed 100644
--- a/system/database/drivers/mysqli/mysqli_driver.php
+++ b/system/database/drivers/mysqli/mysqli_driver.php
@@ -475,6 +475,26 @@ class CI_DB_mysqli_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Close DB Connection
 	 *
 	 * @return	void
diff --git a/system/database/drivers/oci8/oci8_driver.php b/system/database/drivers/oci8/oci8_driver.php
index 7bf18949b..72cbce5c1 100644
--- a/system/database/drivers/oci8/oci8_driver.php
+++ b/system/database/drivers/oci8/oci8_driver.php
@@ -543,22 +543,6 @@ class CI_DB_oci8_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Insert_batch statement
 	 *
 	 * Generates a platform-specific insert string from the supplied data
diff --git a/system/database/drivers/odbc/odbc_driver.php b/system/database/drivers/odbc/odbc_driver.php
index fbf6a4cb1..c1f6ccfe2 100644
--- a/system/database/drivers/odbc/odbc_driver.php
+++ b/system/database/drivers/odbc/odbc_driver.php
@@ -289,22 +289,6 @@ class CI_DB_odbc_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Truncate statement
 	 *
 	 * Generates a platform-specific truncate string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php b/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
index e287f5c63..efc0500a5 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_4d_driver.php
@@ -130,22 +130,6 @@ class CI_DB_pdo_4d_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
index eb3714783..cb18a5c10 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_cubrid_driver.php
@@ -179,6 +179,26 @@ class CI_DB_pdo_cubrid_driver extends CI_DB_pdo_driver {
 		return 'TRUNCATE '.$table;
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
 }
 
 /* End of file pdo_cubrid_driver.php */
diff --git a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
index 7060c9eb9..2346e683e 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
@@ -153,22 +153,6 @@ class CI_DB_pdo_dblib_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php b/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
index c074a9a78..6fba764a9 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
@@ -139,22 +139,6 @@ class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return 	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php b/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
index 832c03c96..399182e12 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_ibm_driver.php
@@ -165,22 +165,6 @@ class CI_DB_pdo_ibm_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php b/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
index a3efc63dc..028121540 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_informix_driver.php
@@ -159,22 +159,6 @@ class CI_DB_pdo_informix_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
index b6807026d..42446889a 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
@@ -207,6 +207,26 @@ class CI_DB_pdo_mysql_driver extends CI_DB_pdo_driver {
 		return 'TRUNCATE '.$table;
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * FROM tables
+	 *
+	 * Groups tables in FROM clauses if needed, so there is no confusion
+	 * about operator precedence.
+	 *
+	 * @return	string
+	 */
+	protected function _from_tables()
+	{
+		if ( ! empty($this->qb_join) && count($this->qb_from) > 1)
+		{
+			return '('.implode(', ', $this->qb_from).')';
+		}
+
+		return implode(', ', $this->qb_from);
+	}
+
 }
 
 /* End of file pdo_mysql_driver.php */
diff --git a/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php b/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
index 56ec1bce1..d584d1f5b 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_oci_driver.php
@@ -146,22 +146,6 @@ class CI_DB_pdo_oci_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Insert_batch statement
 	 *
 	 * @param	string	the table name
diff --git a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
index dd7a1af52..e7ab3fd50 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_odbc_driver.php
@@ -156,22 +156,6 @@ class CI_DB_pdo_odbc_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
index 9a476f143..2a687812a 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_pgsql_driver.php
@@ -142,22 +142,6 @@ class CI_DB_pdo_pgsql_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
index f125b8f50..ee7c1d15a 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_sqlsrv_driver.php
@@ -182,22 +182,6 @@ class CI_DB_pdo_sqlsrv_driver extends CI_DB_pdo_driver {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/postgre/postgre_driver.php b/system/database/drivers/postgre/postgre_driver.php
index 1d6e9567a..2a91a8959 100644
--- a/system/database/drivers/postgre/postgre_driver.php
+++ b/system/database/drivers/postgre/postgre_driver.php
@@ -457,22 +457,6 @@ class CI_DB_postgre_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data
diff --git a/system/database/drivers/sqlsrv/sqlsrv_driver.php b/system/database/drivers/sqlsrv/sqlsrv_driver.php
index abcaf4577..a6739d192 100644
--- a/system/database/drivers/sqlsrv/sqlsrv_driver.php
+++ b/system/database/drivers/sqlsrv/sqlsrv_driver.php
@@ -358,22 +358,6 @@ class CI_DB_sqlsrv_driver extends CI_DB {
 	// --------------------------------------------------------------------
 
 	/**
-	 * From Tables
-	 *
-	 * This function implicitly groups FROM tables so there is no confusion
-	 * about operator precedence in harmony with SQL standards
-	 *
-	 * @param	array
-	 * @return	string
-	 */
-	protected function _from_tables($tables)
-	{
-		return is_array($tables) ? implode(', ', $tables) : $tables;
-	}
-
-	// --------------------------------------------------------------------
-
-	/**
 	 * Update statement
 	 *
 	 * Generates a platform-specific update string from the supplied data