From: Mike Bayer Date: Fri, 25 Aug 2017 13:41:18 +0000 (-0400) Subject: Allow for multiple FOLLOWING/PRECEDING in a window range X-Git-Tag: rel_1_1_14~9 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fb55270835b18e6ba942b74ee72719ce0fc4d062;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git Allow for multiple FOLLOWING/PRECEDING in a window range Altered the range specification for window functions to allow for two of the same PRECEDING or FOLLOWING keywords in a range by allowing for the left side of the range to be positive and for the right to be negative, e.g. (1, 3) is "1 FOLLOWING AND 3 FOLLOWING". Change-Id: I7d3a6c641151bb49219104968d18dac2266f3db8 Fixes: #4053 (cherry picked from commit 3a5bbe4cbe12d180fba2b942d0467b46be705bea) --- diff --git a/doc/build/changelog/unreleased_11/4053.rst b/doc/build/changelog/unreleased_11/4053.rst new file mode 100644 index 0000000000..718b58fb8f --- /dev/null +++ b/doc/build/changelog/unreleased_11/4053.rst @@ -0,0 +1,9 @@ +.. change:: + :tags: bug, sql + :tickets: 4053 + + Altered the range specification for window functions to allow + for two of the same PRECEDING or FOLLOWING keywords in a range + by allowing for the left side of the range to be positive + and for the right to be negative, e.g. (1, 3) is + "1 FOLLOWING AND 3 FOLLOWING". diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py index 6768c062e5..985cf4db3b 100644 --- a/lib/sqlalchemy/sql/compiler.py +++ b/lib/sqlalchemy/sql/compiler.py @@ -832,16 +832,25 @@ class SQLCompiler(Compiled): cast.typeclause._compiler_dispatch(self, **kwargs)) def _format_frame_clause(self, range_, **kw): + return '%s AND %s' % ( "UNBOUNDED PRECEDING" if range_[0] is elements.RANGE_UNBOUNDED else "CURRENT ROW" if range_[0] is elements.RANGE_CURRENT - else "%s PRECEDING" % (self.process(range_[0], **kw), ), + else "%s PRECEDING" % ( + self.process(elements.literal(abs(range_[0])), **kw), ) + if range_[0] < 0 + else "%s FOLLOWING" % ( + self.process(elements.literal(range_[0]), **kw), ), "UNBOUNDED FOLLOWING" if range_[1] is elements.RANGE_UNBOUNDED else "CURRENT ROW" if range_[1] is elements.RANGE_CURRENT - else "%s FOLLOWING" % (self.process(range_[1], **kw), ) + else "%s PRECEDING" % ( + self.process(elements.literal(abs(range_[1])), **kw), ) + if range_[1] < 0 + else "%s FOLLOWING" % ( + self.process(elements.literal(range_[1]), **kw), ), ) def visit_over(self, over, **kwargs): diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py index aacafa6926..af90f3ac57 100644 --- a/lib/sqlalchemy/sql/elements.py +++ b/lib/sqlalchemy/sql/elements.py @@ -3136,6 +3136,10 @@ class Over(ColumnElement): func.row_number().over(order_by='x', range_=(-2, None)) + * RANGE BETWEEN 1 FOLLOWING AND 3 FOLLOWING:: + + func.row_number().over(order_by='x', range_=(1, 3)) + .. versionadded:: 1.1 support for RANGE / ROWS within a window @@ -3197,42 +3201,30 @@ class Over(ColumnElement): raise exc.ArgumentError("2-tuple expected for range/rows") if range_[0] is None: - preceding = RANGE_UNBOUNDED + lower = RANGE_UNBOUNDED else: try: - preceding = int(range_[0]) + lower = int(range_[0]) except ValueError: raise exc.ArgumentError( - "Integer or None expected for preceding value") + "Integer or None expected for range value") else: - if preceding > 0: - raise exc.ArgumentError( - "Preceding value must be a " - "negative integer, zero, or None") - elif preceding < 0: - preceding = literal(abs(preceding)) - else: - preceding = RANGE_CURRENT + if lower == 0: + lower = RANGE_CURRENT if range_[1] is None: - following = RANGE_UNBOUNDED + upper = RANGE_UNBOUNDED else: try: - following = int(range_[1]) + upper = int(range_[1]) except ValueError: raise exc.ArgumentError( - "Integer or None expected for following value") + "Integer or None expected for range value") else: - if following < 0: - raise exc.ArgumentError( - "Following value must be a positive " - "integer, zero, or None") - elif following > 0: - following = literal(following) - else: - following = RANGE_CURRENT + if upper == 0: + upper = RANGE_CURRENT - return preceding, following + return lower, upper @property def func(self): diff --git a/test/sql/test_compiler.py b/test/sql/test_compiler.py index e65db2a36d..d74783236e 100644 --- a/test/sql/test_compiler.py +++ b/test/sql/test_compiler.py @@ -2412,31 +2412,37 @@ class SelectTest(fixtures.TestBase, AssertsCompiledSQL): "(ORDER BY mytable.myid RANGE BETWEEN " ":param_1 PRECEDING AND :param_2 FOLLOWING)" " AS anon_1 FROM mytable", - {'param_1': 5, 'param_2': 10} + checkparams={'param_1': 5, 'param_2': 10} ) - def test_over_invalid_framespecs(self): - assert_raises_message( - exc.ArgumentError, - "Preceding value must be a negative integer, zero, or None", - func.row_number().over, range_=(5, 10) + self.assert_compile( + select([func.row_number().over(order_by=expr, range_=(1, 10))]), + "SELECT row_number() OVER " + "(ORDER BY mytable.myid RANGE BETWEEN " + ":param_1 FOLLOWING AND :param_2 FOLLOWING)" + " AS anon_1 FROM mytable", + checkparams={'param_1': 1, 'param_2': 10} ) - assert_raises_message( - exc.ArgumentError, - "Following value must be a positive integer, zero, or None", - func.row_number().over, range_=(-5, -8) + self.assert_compile( + select([func.row_number().over(order_by=expr, range_=(-10, -1))]), + "SELECT row_number() OVER " + "(ORDER BY mytable.myid RANGE BETWEEN " + ":param_1 PRECEDING AND :param_2 PRECEDING)" + " AS anon_1 FROM mytable", + checkparams={'param_1': 10, 'param_2': 1} ) + def test_over_invalid_framespecs(self): assert_raises_message( exc.ArgumentError, - "Integer or None expected for preceding value", + "Integer or None expected for range value", func.row_number().over, range_=("foo", 8) ) assert_raises_message( exc.ArgumentError, - "Integer or None expected for following value", + "Integer or None expected for range value", func.row_number().over, range_=(-5, "foo") )