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108 lines
3.0 KiB
108 lines
3.0 KiB
# encoding: utf-8
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#
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# This Source Code Form is subject to the terms of the Mozilla Public
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# License, v. 2.0. If a copy of the MPL was not distributed with this file,
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# You can obtain one at http://mozilla.org/MPL/2.0/.
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#
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# Contact: Kyle Lahnakoski (kyle@lahnakoski.com)
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#
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from __future__ import absolute_import, division, unicode_literals
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from mo_parsing.infix import delimited_list
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from aquery_parser.keywords import *
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from aquery_parser.utils import *
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# https://docs.microsoft.com/en-us/sql/t-sql/queries/select-over-clause-transact-sql?view=sql-server-ver15
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def _to_bound_call(tokens):
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zero = tokens["zero"]
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if zero:
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return {"min": 0, "max": 0}
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direction = scrub(tokens["direction"])
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limit = scrub(tokens["limit"])
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if direction == "preceding":
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if limit == "unbounded":
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return {"max": 0}
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elif is_data(limit):
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return {"min": {"neg": limit}, "max": 0}
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else:
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return {"min": -limit, "max": 0}
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else: # following
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if limit == "unbounded":
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return {"min": 0}
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elif is_data(limit):
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return {"min": {"neg": limit}, "max": 0}
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else:
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return {"min": 0, "max": limit}
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def _to_between_call(tokens):
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minn = scrub(tokens["min"])
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maxx = scrub(tokens["max"])
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if maxx.get("max") == 0:
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# following
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return {
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"min": minn.get("min"),
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"max": maxx.get("min"),
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}
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elif minn.get("min") == 0:
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# preceding
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return {"min": minn.get("max"), "max": maxx.get("max")}
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else:
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return {
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"min": minn.get("min"),
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"max": maxx.get("max"),
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}
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UNBOUNDED = keyword("unbounded")
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PRECEDING = keyword("preceding")
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FOLLOWING = keyword("following")
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CURRENT_ROW = keyword("current row")
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ROWS = keyword("rows")
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RANGE = keyword("range")
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def window(expr, var_name, sort_column):
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bound_row = (
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CURRENT_ROW("zero")
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| (UNBOUNDED | int_num)("limit") + (PRECEDING | FOLLOWING)("direction")
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) / _to_bound_call
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bound_expr = (
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CURRENT_ROW("zero")
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| (UNBOUNDED | expr)("limit") + (PRECEDING | FOLLOWING)("direction")
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) / _to_bound_call
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between_row = (
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BETWEEN + bound_row("min") + AND + bound_row("max")
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) / _to_between_call
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between_expr = (
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BETWEEN + bound_expr("min") + AND + bound_expr("max")
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) / _to_between_call
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row_clause = (ROWS.suppress() + (between_row | bound_row)) | (
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RANGE.suppress() + (between_expr | bound_expr)
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)
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over_clause = (
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LB
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+ Optional(PARTITION_BY + delimited_list(Group(expr))("partitionby"))
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+ Optional(ORDER_BY + delimited_list(Group(sort_column))("orderby"))
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+ Optional(row_clause("range"))
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+ RB
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)
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window_clause = Optional((
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WITHIN_GROUP
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+ LB
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+ Optional(ORDER_BY + delimited_list(Group(sort_column))("orderby"))
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+ RB
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)("within")) + ((OVER + (over_clause | var_name) / to_over)("over"))
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return window_clause, over_clause
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