silverstripe-framework/docs/en/changelogs/4.0.0.md

# 4.0.0 (unreleased)

## Overview

### Framework

 * Deprecate `SQLQuery` in favour `SQLSelect`
 * `DataList::filter` by null now internally generates "IS NULL" or "IS NOT NULL" conditions appropriately on queries

## Upgrading

### Update code that uses SQLQuery

SQLQuery is still implemented, but now extends the new SQLSelect class and has some methods
deprecated. Previously this class was used for both selecting and deleting, but these
have been superceded by the specialised SQLSelect and SQLDelete classes.

Take care for any code or functions which expect an object of type `SQLQuery`, as
these references should be replaced with `SQLSelect`. Legacy code which generates
`SQLQuery` can still communicate with new code that expects `SQLSelect` as it is a
subclass of `SQLSelect`, but the inverse is not true.

### Update implementations of augmentSQL

Since this method now takes a `SQLSelect` as a first parameter, existing code referencing the deprecated `SQLQuery`
type will raise a PHP error.

E.g.

Before:

	:::php
	function augmentSQL(SQLQuery &$query, DataQuery &$dataQuery = null) {
		$locale = Translatable::get_current_locale();
		if(!preg_match('/("|\'|`)Locale("|\'|`)/', implode(' ', $query->getWhere())))  {
			$qry = sprintf('"Locale" = \'%s\'', Convert::raw2sql($locale));
			$query->addWhere($qry); 
		}
	}

After:

	:::php
	function augmentSQL(SQLSelect $query, DataQuery $dataQuery = null) {
		$locale = Translatable::get_current_locale();
		if(!preg_match('/("|\'|`)Locale("|\'|`)/', implode(' ', $query->getWhereParameterised($parameters))))  {
			$query->addWhere(array(
				'"Locale"' => $locale
			));
		}
	}