id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
36845	Allow negative index in Left() for PostgreSQL	Christopher Covington	Moksha Choksi	"PostgreSQL has supported negative indices since v9.1 https://www.postgresql.org/docs/9.1/functions-string.html as right side trim length--just like Python string slicing.

Targeting the check and ValueError in `Left.__init__()` more precisely will enable straightforward translation of a common string manipulation pattern from Python:
`field[:-3]`

to Django ORM for PostgreSQL:
`Left('field', -3)`

For other databases I would propose initially carrying forward the non-negative requirement. If there's interest, a Python implementation of negative index (right side trim length) support, or something cleverer, could follow up as separate discussion and work."	New feature	closed	Database layer (models, ORM)	6.0	Normal	needsnewfeatureprocess		Christopher Covington	Unreviewed	0	0	0	0	0	0