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Declare lead() and lag() using anycompatible not anyelement.
This allows use of a "default" expression that doesn't slavishly match the data column's type. Formerly you got something like "function lag(numeric, integer, integer) does not exist", which is not just unhelpful but actively misleading. The SQL spec suggests that the default should be coerced to the data column's type, but this implementation instead chooses the common supertype, which seems at least as reasonable. (Note: I took the opportunity to run "make reformat-dat-files" on pg_proc.dat, so this commit includes some cosmetic changes to recently-added entries that aren't related to lead/lag.) Vik Fearing Discussion: https://postgr.es/m/77675130-89da-dab1-51dd-492c93dcf5d1@postgresfriends.org
This commit is contained in:
Tom Lane
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40c24bfef9
commit
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@ -19594,17 +19594,17 @@ SELECT count(*) FROM sometable;
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<indexterm>
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<primary>lag</primary>
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</indexterm>
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<function>lag</function> ( <parameter>value</parameter> <type>anyelement</type>
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<function>lag</function> ( <parameter>value</parameter> <type>anycompatible</type>
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<optional>, <parameter>offset</parameter> <type>integer</type>
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<optional>, <parameter>default</parameter> <type>anyelement</type> </optional></optional> )
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<returnvalue>anyelement</returnvalue>
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<optional>, <parameter>default</parameter> <type>anycompatible</type> </optional></optional> )
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<returnvalue>anycompatible</returnvalue>
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</para>
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<para>
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Returns <parameter>value</parameter> evaluated at
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the row that is <parameter>offset</parameter>
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rows before the current row within the partition; if there is no such
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row, instead returns <parameter>default</parameter>
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(which must be of the same type as
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(which must be of a type compatible with
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<parameter>value</parameter>).
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Both <parameter>offset</parameter> and
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<parameter>default</parameter> are evaluated
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@ -19619,17 +19619,17 @@ SELECT count(*) FROM sometable;
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<indexterm>
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<primary>lead</primary>
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</indexterm>
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<function>lead</function> ( <parameter>value</parameter> <type>anyelement</type>
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<function>lead</function> ( <parameter>value</parameter> <type>anycompatible</type>
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<optional>, <parameter>offset</parameter> <type>integer</type>
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<optional>, <parameter>default</parameter> <type>anyelement</type> </optional></optional> )
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<returnvalue>anyelement</returnvalue>
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<optional>, <parameter>default</parameter> <type>anycompatible</type> </optional></optional> )
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<returnvalue>anycompatible</returnvalue>
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</para>
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<para>
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Returns <parameter>value</parameter> evaluated at
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the row that is <parameter>offset</parameter>
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rows after the current row within the partition; if there is no such
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row, instead returns <parameter>default</parameter>
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(which must be of the same type as
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(which must be of a type compatible with
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<parameter>value</parameter>).
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Both <parameter>offset</parameter> and
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<parameter>default</parameter> are evaluated
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@ -53,6 +53,6 @@
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*/
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/* yyyymmddN */
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#define CATALOG_VERSION_NO 202011042
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#define CATALOG_VERSION_NO 202011043
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#endif
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@ -1563,11 +1563,11 @@
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proname => 'string_to_array', proisstrict => 'f', prorettype => '_text',
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proargtypes => 'text text text', prosrc => 'text_to_array_null' },
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{ oid => '8432', descr => 'split delimited text',
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proname => 'string_to_table', proisstrict => 'f', prorows => '1000',
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proname => 'string_to_table', prorows => '1000', proisstrict => 'f',
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proretset => 't', prorettype => 'text', proargtypes => 'text text',
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prosrc => 'text_to_table' },
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{ oid => '8433', descr => 'split delimited text, with null string',
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proname => 'string_to_table', proisstrict => 'f', prorows => '1000',
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proname => 'string_to_table', prorows => '1000', proisstrict => 'f',
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proretset => 't', prorettype => 'text', proargtypes => 'text text text',
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prosrc => 'text_to_table_null' },
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{ oid => '395',
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@ -5257,8 +5257,8 @@
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proargnames => '{pid,status,receive_start_lsn,receive_start_tli,written_lsn,flushed_lsn,received_tli,last_msg_send_time,last_msg_receipt_time,latest_end_lsn,latest_end_time,slot_name,sender_host,sender_port,conninfo}',
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prosrc => 'pg_stat_get_wal_receiver' },
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{ oid => '8595', descr => 'statistics: information about replication slots',
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proname => 'pg_stat_get_replication_slots', prorows => '10', proisstrict => 'f',
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proretset => 't', provolatile => 's', proparallel => 'r',
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proname => 'pg_stat_get_replication_slots', prorows => '10',
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proisstrict => 'f', proretset => 't', provolatile => 's', proparallel => 'r',
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prorettype => 'record', proargtypes => '',
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proallargtypes => '{text,int8,int8,int8,int8,int8,int8,timestamptz}',
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proargmodes => '{o,o,o,o,o,o,o,o}',
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@ -5491,8 +5491,7 @@
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{ oid => '1136', descr => 'statistics: information about WAL activity',
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proname => 'pg_stat_get_wal', proisstrict => 'f', provolatile => 's',
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proparallel => 'r', prorettype => 'record', proargtypes => '',
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proallargtypes => '{int8,timestamptz}',
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proargmodes => '{o,o}',
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proallargtypes => '{int8,timestamptz}', proargmodes => '{o,o}',
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proargnames => '{wal_buffers_full,stats_reset}',
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prosrc => 'pg_stat_get_wal' },
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@ -5615,8 +5614,9 @@
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prorettype => 'void', proargtypes => 'text', prosrc => 'pg_stat_reset_slru' },
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{ oid => '8596',
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descr => 'statistics: reset collected statistics for a single replication slot',
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proname => 'pg_stat_reset_replication_slot', proisstrict => 'f', provolatile => 'v',
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prorettype => 'void', proargtypes => 'text', prosrc => 'pg_stat_reset_replication_slot' },
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proname => 'pg_stat_reset_replication_slot', proisstrict => 'f',
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provolatile => 'v', prorettype => 'void', proargtypes => 'text',
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prosrc => 'pg_stat_reset_replication_slot' },
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{ oid => '3163', descr => 'current trigger depth',
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proname => 'pg_trigger_depth', provolatile => 's', proparallel => 'r',
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@ -7833,9 +7833,11 @@
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prosrc => 'pg_get_shmem_allocations' },
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# memory context of local backend
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{ oid => '2282', descr => 'information about all memory contexts of local backend',
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proname => 'pg_get_backend_memory_contexts', prorows => '100', proretset => 't',
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provolatile => 'v', proparallel => 'r', prorettype => 'record', proargtypes => '',
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{ oid => '2282',
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descr => 'information about all memory contexts of local backend',
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proname => 'pg_get_backend_memory_contexts', prorows => '100',
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proretset => 't', provolatile => 'v', proparallel => 'r',
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prorettype => 'record', proargtypes => '',
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proallargtypes => '{text,text,text,int4,int8,int8,int8,int8,int8}',
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proargmodes => '{o,o,o,o,o,o,o,o,o}',
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proargnames => '{name, ident, parent, level, total_bytes, total_nblocks, free_bytes, free_chunks, used_bytes}',
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@ -9748,8 +9750,8 @@
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proname => 'lag', prokind => 'w', prorettype => 'anyelement',
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proargtypes => 'anyelement int4', prosrc => 'window_lag_with_offset' },
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{ oid => '3108', descr => 'fetch the Nth preceding row value with default',
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proname => 'lag', prokind => 'w', prorettype => 'anyelement',
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proargtypes => 'anyelement int4 anyelement',
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proname => 'lag', prokind => 'w', prorettype => 'anycompatible',
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proargtypes => 'anycompatible int4 anycompatible',
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prosrc => 'window_lag_with_offset_and_default' },
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{ oid => '3109', descr => 'fetch the following row value',
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proname => 'lead', prokind => 'w', prorettype => 'anyelement',
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@ -9758,8 +9760,8 @@
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proname => 'lead', prokind => 'w', prorettype => 'anyelement',
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proargtypes => 'anyelement int4', prosrc => 'window_lead_with_offset' },
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{ oid => '3111', descr => 'fetch the Nth following row value with default',
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proname => 'lead', prokind => 'w', prorettype => 'anyelement',
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proargtypes => 'anyelement int4 anyelement',
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proname => 'lead', prokind => 'w', prorettype => 'anycompatible',
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proargtypes => 'anycompatible int4 anycompatible',
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prosrc => 'window_lead_with_offset_and_default' },
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{ oid => '3112', descr => 'fetch the first row value',
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proname => 'first_value', prokind => 'w', prorettype => 'anyelement',
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@ -300,6 +300,21 @@ SELECT lag(ten, four, 0) OVER (PARTITION BY four ORDER BY ten), ten, four FROM t
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0 | 3 | 3
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(10 rows)
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SELECT lag(ten, four, 0.7) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10 ORDER BY four, ten;
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lag | ten | four
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-----+-----+------
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0 | 0 | 0
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0 | 0 | 0
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4 | 4 | 0
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0.7 | 1 | 1
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1 | 1 | 1
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1 | 7 | 1
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7 | 9 | 1
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0.7 | 0 | 2
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0.7 | 1 | 3
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0.7 | 3 | 3
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(10 rows)
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SELECT lead(ten) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10;
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lead | ten | four
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------+-----+------
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@ -345,6 +360,21 @@ SELECT lead(ten * 2, 1, -1) OVER (PARTITION BY four ORDER BY ten), ten, four FRO
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-1 | 3 | 3
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(10 rows)
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SELECT lead(ten * 2, 1, -1.4) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10 ORDER BY four, ten;
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lead | ten | four
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------+-----+------
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0 | 0 | 0
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8 | 0 | 0
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-1.4 | 4 | 0
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2 | 1 | 1
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14 | 1 | 1
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18 | 7 | 1
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-1.4 | 9 | 1
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-1.4 | 0 | 2
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6 | 1 | 3
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-1.4 | 3 | 3
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(10 rows)
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SELECT first_value(ten) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10;
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first_value | ten | four
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-------------+-----+------
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@ -63,12 +63,14 @@ SELECT lag(ten) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHER
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SELECT lag(ten, four) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10;
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SELECT lag(ten, four, 0) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10;
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SELECT lag(ten, four, 0.7) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10 ORDER BY four, ten;
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SELECT lead(ten) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10;
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SELECT lead(ten * 2, 1) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10;
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SELECT lead(ten * 2, 1, -1) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10;
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SELECT lead(ten * 2, 1, -1.4) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10 ORDER BY four, ten;
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SELECT first_value(ten) OVER (PARTITION BY four ORDER BY ten), ten, four FROM tenk1 WHERE unique2 < 10;
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