Add a method to the get "to use" table and column name

lib/private/db/querybuilder/querybuilder.php

@@ -1061,14 +1061,31 @@ class QueryBuilder implements IQueryBuilder {
 	}
 
 	/**
+	 * Returns the table name quoted and with database prefix as needed by the implementation
+	 *
 	 * @param string $table
 	 * @return string
 	 */
-	private function getTableName($table) {
+	public function getTableName($table) {
 		if ($this->automaticTablePrefix === false || strpos($table, '*PREFIX*') === 0) {
 			return $this->helper->quoteColumnName($table);
 		}
 
 		return $this->helper->quoteColumnName('*PREFIX*' . $table);
 	}
+
+	/**
+	 * Returns the column name quoted and with table alias prefix as needed by the implementation
+	 *
+	 * @param string $column
+	 * @param string $tableAlias
+	 * @return string
+	 */
+	public function getColumnName($column, $tableAlias = '') {
+		if ($tableAlias !== '') {
+			$tableAlias .= '.';
+		}
+
+		return $this->helper->quoteColumnName($tableAlias . $column);
+	}
 }

lib/private/db/querybuilder/quotehelper.php

@@ -61,7 +61,7 @@ class QuoteHelper {
 		}
 
 		if (substr_count($string, '.')) {
-			list($alias, $columnName) = explode('.', $string);
+			list($alias, $columnName) = explode('.', $string, 2);
 
 			if ($columnName === '*') {
 				return $string;

lib/public/db/querybuilder/iquerybuilder.php

@@ -820,4 +820,23 @@ interface IQueryBuilder {
 	 * @since 9.0.0
 	 */
 	public function getLastInsertId();
+
+	/**
+	 * Returns the table name quoted and with database prefix as needed by the implementation
+	 *
+	 * @param string $table
+	 * @return string
+	 * @since 9.0.0
+	 */
+	public function getTableName($table);
+
+	/**
+	 * Returns the column name quoted and with table alias prefix as needed by the implementation
+	 *
+	 * @param string $column
+	 * @param string $tableAlias
+	 * @return string
+	 * @since 9.0.0
+	 */
+	public function getColumnName($column, $tableAlias = '');
 }

tests/lib/db/querybuilder/querybuildertest.php

@@ -1165,7 +1165,27 @@ class QueryBuilderTest extends \Test\TestCase {
 
 		$this->assertSame(
 			$expected,
-			$this->invokePrivate($this->queryBuilder, 'getTableName', [$tableName])
+			$this->queryBuilder->getTableName($tableName)
+		);
+	}
+
+	public function dataGetColumnName() {
+		return [
+			['column', '', '`column`'],
+			['column', 'a', 'a.`column`'],
+		];
+	}
+
+	/**
+	 * @dataProvider dataGetColumnName
+	 * @param string $column
+	 * @param string $prefix
+	 * @param string $expected
+	 */
+	public function testGetColumnName($column, $prefix, $expected) {
+		$this->assertSame(
+			$expected,
+			$this->queryBuilder->getColumnName($column, $prefix)
 		);
 	}
 }