diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 4c5af4b..89d28b2 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -12266,6 +12266,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
lag(value any
[, offset integer
[, default any ]])
+ [respect nulls]|[ignore nulls]
@@ -12280,7 +12281,10 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
default are evaluated
with respect to the current row. If omitted,
offset defaults to 1 and
- default to null
+ default to null. If
+ IGNORE NULLS is specified and a previous evalution in the
+ current window has returned a non-null value then that value will be
+ returned instead.
@@ -12293,6 +12297,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
lead(value any
[, offset integer
[, default any ]])
+ [respect nulls]|[ignore nulls]
@@ -12307,7 +12312,9 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
default are evaluated
with respect to the current row. If omitted,
offset defaults to 1 and
- default to null
+ IGNORE NULLS is specified and a previous evalution in the
+ current window has returned a non-null value then that value will be
+ returned instead.
@@ -12401,11 +12408,10 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
The SQL standard defines a RESPECT NULLS or
- IGNORE NULLS option for lead, lag,
- first_value, last_value, and
- nth_value. This is not implemented in
- PostgreSQL: the behavior is always the
- same as the standard's default, namely RESPECT NULLS.
+ IGNORE NULLS option for first_value,
+ last_value, and nth_value. This is not
+ implemented in PostgreSQL: the behavior is
+ always the same as the standard's default, namely RESPECT NULLS.
Likewise, the standard's FROM FIRST or FROM LAST
option for nth_value is not implemented: only the
default FROM FIRST behavior is supported. (You can achieve
diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c
index d9f0e79..e1a1020 100644
--- a/src/backend/executor/nodeWindowAgg.c
+++ b/src/backend/executor/nodeWindowAgg.c
@@ -2000,6 +2000,16 @@ WinGetCurrentPosition(WindowObject winobj)
Assert(WindowObjectIsValid(winobj));
return winobj->winstate->currentpos;
}
+/*
+ * WinGetFrameOptions
+ * Returns the frame option flags
+ */
+int
+WinGetFrameOptions(WindowObject winobj)
+{
+ Assert(WindowObjectIsValid(winobj));
+ return winobj->winstate->frameOptions;
+}
/*
* WinGetPartitionRowCount
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 5094226..aae35d8 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -288,6 +288,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
%type TriggerEvents TriggerOneEvent
%type TriggerFuncArg
%type TriggerWhen
+%type opt_ignore_nulls
%type event_trigger_when_list event_trigger_value_list
%type event_trigger_when_item
@@ -401,7 +402,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
%type columnDef columnOptions
%type def_elem reloption_elem old_aggr_elem
%type def_arg columnElem where_clause where_or_current_clause
- a_expr b_expr c_expr func_expr AexprConst indirection_el
+ a_expr b_expr c_expr AexprConst indirection_el
columnref in_expr having_clause func_table array_expr
ExclusionWhereClause
%type ExclusionConstraintList ExclusionConstraintElem
@@ -481,6 +482,8 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
%type document_or_content
%type xml_whitespace_option
+%type func_application func_expr_common_subexpr
+%type func_expr func_expr_windowless
%type common_table_expr
%type with_clause opt_with_clause
%type cte_list
@@ -543,7 +546,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
HANDLER HAVING HEADER_P HOLD HOUR_P
- IDENTITY_P IF_P ILIKE IMMEDIATE IMMUTABLE IMPLICIT_P IN_P
+ IDENTITY_P IF_P IGNORE ILIKE IMMEDIATE IMMUTABLE IMPLICIT_P IN_P
INCLUDING INCREMENT INDEX INDEXES INHERIT INHERITS INITIALLY INLINE_P
INNER_P INOUT INPUT_P INSENSITIVE INSERT INSTEAD INT_P INTEGER
INTERSECT INTERVAL INTO INVOKER IS ISNULL ISOLATION
@@ -573,7 +576,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
RANGE READ REAL REASSIGN RECHECK RECURSIVE REF REFERENCES REFRESH REINDEX
RELATIVE_P RELEASE RENAME REPEATABLE REPLACE REPLICA
- RESET RESTART RESTRICT RETURNING RETURNS REVOKE RIGHT ROLE ROLLBACK
+ RESET RESPECT RESTART RESTRICT RETURNING RETURNS REVOKE RIGHT ROLE ROLLBACK
ROW ROWS RULE
SAVEPOINT SCHEMA SCROLL SEARCH SECOND_P SECURITY SELECT SEQUENCE SEQUENCES
@@ -6132,7 +6135,7 @@ index_elem: ColId opt_collate opt_class opt_asc_desc opt_nulls_order
$$->ordering = $4;
$$->nulls_ordering = $5;
}
- | func_expr opt_collate opt_class opt_asc_desc opt_nulls_order
+ | func_expr_windowless opt_collate opt_class opt_asc_desc opt_nulls_order
{
$$ = makeNode(IndexElem);
$$->name = NULL;
@@ -9894,11 +9897,9 @@ relation_expr_opt_alias: relation_expr %prec UMINUS
}
;
-
-func_table: func_expr { $$ = $1; }
+func_table: func_expr_windowless { $$ = $1; }
;
-
where_clause:
WHERE a_expr { $$ = $2; }
| /*EMPTY*/ { $$ = NULL; }
@@ -11079,15 +11080,7 @@ c_expr: columnref { $$ = $1; }
}
;
-/*
- * func_expr is split out from c_expr just so that we have a classification
- * for "everything that is a function call or looks like one". This isn't
- * very important, but it saves us having to document which variants are
- * legal in the backwards-compatible functional-index syntax for CREATE INDEX.
- * (Note that many of the special SQL functions wouldn't actually make any
- * sense as functional index entries, but we ignore that consideration here.)
- */
-func_expr: func_name '(' ')' over_clause
+func_application: func_name '(' ')'
{
FuncCall *n = makeNode(FuncCall);
n->funcname = $1;
@@ -11096,11 +11089,11 @@ func_expr: func_name '(' ')' over_clause
n->agg_star = FALSE;
n->agg_distinct = FALSE;
n->func_variadic = FALSE;
- n->over = $4;
+ n->over = NULL;
n->location = @1;
$$ = (Node *)n;
}
- | func_name '(' func_arg_list ')' over_clause
+ | func_name '(' func_arg_list ')'
{
FuncCall *n = makeNode(FuncCall);
n->funcname = $1;
@@ -11109,11 +11102,11 @@ func_expr: func_name '(' ')' over_clause
n->agg_star = FALSE;
n->agg_distinct = FALSE;
n->func_variadic = FALSE;
- n->over = $5;
+ n->over = NULL;
n->location = @1;
$$ = (Node *)n;
}
- | func_name '(' VARIADIC func_arg_expr ')' over_clause
+ | func_name '(' VARIADIC func_arg_expr ')'
{
FuncCall *n = makeNode(FuncCall);
n->funcname = $1;
@@ -11122,11 +11115,11 @@ func_expr: func_name '(' ')' over_clause
n->agg_star = FALSE;
n->agg_distinct = FALSE;
n->func_variadic = TRUE;
- n->over = $6;
+ n->over = NULL;
n->location = @1;
$$ = (Node *)n;
}
- | func_name '(' func_arg_list ',' VARIADIC func_arg_expr ')' over_clause
+ | func_name '(' func_arg_list ',' VARIADIC func_arg_expr ')'
{
FuncCall *n = makeNode(FuncCall);
n->funcname = $1;
@@ -11135,11 +11128,11 @@ func_expr: func_name '(' ')' over_clause
n->agg_star = FALSE;
n->agg_distinct = FALSE;
n->func_variadic = TRUE;
- n->over = $8;
+ n->over = NULL;
n->location = @1;
$$ = (Node *)n;
}
- | func_name '(' func_arg_list sort_clause ')' over_clause
+ | func_name '(' func_arg_list sort_clause ')'
{
FuncCall *n = makeNode(FuncCall);
n->funcname = $1;
@@ -11148,11 +11141,11 @@ func_expr: func_name '(' ')' over_clause
n->agg_star = FALSE;
n->agg_distinct = FALSE;
n->func_variadic = FALSE;
- n->over = $6;
+ n->over = NULL;
n->location = @1;
$$ = (Node *)n;
}
- | func_name '(' ALL func_arg_list opt_sort_clause ')' over_clause
+ | func_name '(' ALL func_arg_list opt_sort_clause ')'
{
FuncCall *n = makeNode(FuncCall);
n->funcname = $1;
@@ -11165,11 +11158,11 @@ func_expr: func_name '(' ')' over_clause
* for that in FuncCall at the moment.
*/
n->func_variadic = FALSE;
- n->over = $7;
+ n->over = NULL;
n->location = @1;
$$ = (Node *)n;
}
- | func_name '(' DISTINCT func_arg_list opt_sort_clause ')' over_clause
+ | func_name '(' DISTINCT func_arg_list opt_sort_clause ')'
{
FuncCall *n = makeNode(FuncCall);
n->funcname = $1;
@@ -11178,11 +11171,11 @@ func_expr: func_name '(' ')' over_clause
n->agg_star = FALSE;
n->agg_distinct = TRUE;
n->func_variadic = FALSE;
- n->over = $7;
+ n->over = NULL;
n->location = @1;
$$ = (Node *)n;
}
- | func_name '(' '*' ')' over_clause
+ | func_name '(' '*' ')'
{
/*
* We consider AGGREGATE(*) to invoke a parameterless
@@ -11201,11 +11194,48 @@ func_expr: func_name '(' ')' over_clause
n->agg_star = TRUE;
n->agg_distinct = FALSE;
n->func_variadic = FALSE;
- n->over = $5;
+ n->over = NULL;
n->location = @1;
$$ = (Node *)n;
}
- | COLLATION FOR '(' a_expr ')'
+ ;
+
+
+/*
+ * func_expr and its cousin func_expr_windowless is split out from c_expr just
+ * so that we have classifications for "everything that is a function call or
+ * looks like one". This isn't very important, but it saves us having to document
+ * which variants are legal in the backwards-compatible functional-index syntax
+ * for CREATE INDEX.
+ * (Note that many of the special SQL functions wouldn't actually make any
+ * sense as functional index entries, but we ignore that consideration here.)
+ */
+func_expr: func_application over_clause
+ {
+ FuncCall *n = (FuncCall*)$1;
+ n->over = $2;
+ $$ = (Node*)n;
+ }
+ | func_expr_common_subexpr
+ { $$ = $1; }
+ ;
+
+/*
+ * As func_expr but does not accept WINDOW functions directly (they
+ * can still be contained in arguments for functions etc.)
+ * Use this when window expressions are not allowed, so to decomplicate
+ * the grammar. (e.g. in CREATE INDEX)
+ */
+func_expr_windowless:
+ func_application { $$ = $1; }
+ | func_expr_common_subexpr { $$ = $1; }
+ ;
+
+/*
+ * Special expression
+ */
+func_expr_common_subexpr:
+ COLLATION FOR '(' a_expr ')'
{
FuncCall *n = makeNode(FuncCall);
n->funcname = SystemFuncName("pg_collation_for");
@@ -11752,16 +11782,25 @@ window_definition:
}
;
-over_clause: OVER window_specification
- { $$ = $2; }
- | OVER ColId
+opt_ignore_nulls:
+ IGNORE NULLS_P { $$ = FRAMEOPTION_IGNORE_NULLS; }
+ | RESPECT NULLS_P { $$ = 0; }
+ | /* EMPTY */ { $$ = 0; }
+ ;
+
+over_clause: opt_ignore_nulls OVER window_specification
+ {
+ $3->frameOptions |= $1;
+ $$ = $3;
+ }
+ | opt_ignore_nulls OVER ColId
{
WindowDef *n = makeNode(WindowDef);
- n->name = $2;
+ n->name = $3;
n->refname = NULL;
n->partitionClause = NIL;
n->orderClause = NIL;
- n->frameOptions = FRAMEOPTION_DEFAULTS;
+ n->frameOptions = FRAMEOPTION_DEFAULTS | $1;
n->startOffset = NULL;
n->endOffset = NULL;
n->location = @2;
@@ -12740,6 +12779,7 @@ unreserved_keyword:
| HOUR_P
| IDENTITY_P
| IF_P
+ | IGNORE
| IMMEDIATE
| IMMUTABLE
| IMPLICIT_P
@@ -12827,6 +12867,7 @@ unreserved_keyword:
| REPLACE
| REPLICA
| RESET
+ | RESPECT
| RESTART
| RESTRICT
| RETURNS
diff --git a/src/backend/utils/adt/windowfuncs.c b/src/backend/utils/adt/windowfuncs.c
index b7c42d3..8985149 100644
--- a/src/backend/utils/adt/windowfuncs.c
+++ b/src/backend/utils/adt/windowfuncs.c
@@ -25,6 +25,15 @@ typedef struct rank_context
} rank_context;
/*
+ * structure for IGNORE NULLS / RESPECT NULLS semantics
+ */
+typedef struct leadlag_context
+{
+ int64 last; /* last non-null result, initially 0 */
+ bool seen_one; /* true iff we can output the row in "last" now */
+} leadlag_context;
+
+/*
* ntile process information
*/
typedef struct
@@ -292,6 +301,15 @@ leadlag_common(FunctionCallInfo fcinfo,
Datum result;
bool isnull;
bool isout;
+ bool ignore_nulls;
+ leadlag_context* context;
+
+ /*
+ * We want to set the markpos (the earliest tuple we can access) as
+ * aggressively as possible to save memory, but we can't move the mark
+ * beyond the last non-null tuple!
+ */
+ ignore_nulls = (WinGetFrameOptions(winobj) & FRAMEOPTION_IGNORE_NULLS) != 0;
if (withoffset)
{
@@ -305,11 +323,15 @@ leadlag_common(FunctionCallInfo fcinfo,
offset = 1;
const_offset = true;
}
+ if(!forward)
+ {
+ offset = -offset;
+ }
result = WinGetFuncArgInPartition(winobj, 0,
- (forward ? offset : -offset),
+ offset,
WINDOW_SEEK_CURRENT,
- const_offset,
+ const_offset && !ignore_nulls,
&isnull, &isout);
if (isout)
@@ -322,6 +344,39 @@ leadlag_common(FunctionCallInfo fcinfo,
result = WinGetFuncArgCurrent(winobj, 2, &isnull);
}
+ /*
+ * If the row's out of the partition we don't want to propagate the
+ * last non-null value if we're RESPECTing NULLS - we'll just leave
+ * the default value (if there was one).
+ */
+ if (ignore_nulls && !isout)
+ {
+ /*
+ * We'll keep the last non-null value we've seen in our per-partition chunk
+ * of memory, so it gets cleaned up for us.
+ */
+ context = (leadlag_context *)
+ WinGetPartitionLocalMemory(winobj, sizeof(leadlag_context));
+ if (isnull)
+ {
+ if (context->seen_one)
+ {
+ /* restore the datum at the stashed index */
+ result = WinGetFuncArgInPartition(winobj, 0,
+ context->last,
+ WINDOW_SEEK_HEAD,
+ const_offset, /* drag mark up after us */
+ &isnull, &isout);
+ }
+ }
+ else
+ {
+ /* work out which tuple we just loaded */
+ context->last = WinGetCurrentPosition(winobj) + offset;
+ context->seen_one = true;
+ }
+ }
+
if (isnull)
PG_RETURN_NULL();
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 6723647..71b44d5 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -435,6 +435,7 @@ typedef struct WindowDef
#define FRAMEOPTION_END_VALUE_PRECEDING 0x00800 /* end is V. P. */
#define FRAMEOPTION_START_VALUE_FOLLOWING 0x01000 /* start is V. F. */
#define FRAMEOPTION_END_VALUE_FOLLOWING 0x02000 /* end is V. F. */
+#define FRAMEOPTION_IGNORE_NULLS 0x04000
#define FRAMEOPTION_START_VALUE \
(FRAMEOPTION_START_VALUE_PRECEDING | FRAMEOPTION_START_VALUE_FOLLOWING)
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index 68a13b7..2acf073 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -179,6 +179,7 @@ PG_KEYWORD("hold", HOLD, UNRESERVED_KEYWORD)
PG_KEYWORD("hour", HOUR_P, UNRESERVED_KEYWORD)
PG_KEYWORD("identity", IDENTITY_P, UNRESERVED_KEYWORD)
PG_KEYWORD("if", IF_P, UNRESERVED_KEYWORD)
+PG_KEYWORD("ignore", IGNORE, UNRESERVED_KEYWORD)
PG_KEYWORD("ilike", ILIKE, TYPE_FUNC_NAME_KEYWORD)
PG_KEYWORD("immediate", IMMEDIATE, UNRESERVED_KEYWORD)
PG_KEYWORD("immutable", IMMUTABLE, UNRESERVED_KEYWORD)
@@ -312,6 +313,7 @@ PG_KEYWORD("repeatable", REPEATABLE, UNRESERVED_KEYWORD)
PG_KEYWORD("replace", REPLACE, UNRESERVED_KEYWORD)
PG_KEYWORD("replica", REPLICA, UNRESERVED_KEYWORD)
PG_KEYWORD("reset", RESET, UNRESERVED_KEYWORD)
+PG_KEYWORD("respect", RESPECT, UNRESERVED_KEYWORD)
PG_KEYWORD("restart", RESTART, UNRESERVED_KEYWORD)
PG_KEYWORD("restrict", RESTRICT, UNRESERVED_KEYWORD)
PG_KEYWORD("returning", RETURNING, RESERVED_KEYWORD)
diff --git a/src/include/windowapi.h b/src/include/windowapi.h
index 5bbf1fa..81f5ba0 100644
--- a/src/include/windowapi.h
+++ b/src/include/windowapi.h
@@ -46,6 +46,8 @@ extern void *WinGetPartitionLocalMemory(WindowObject winobj, Size sz);
extern int64 WinGetCurrentPosition(WindowObject winobj);
extern int64 WinGetPartitionRowCount(WindowObject winobj);
+extern int WinGetFrameOptions(WindowObject winobj);
+
extern void WinSetMarkPosition(WindowObject winobj, int64 markpos);
extern bool WinRowsArePeers(WindowObject winobj, int64 pos1, int64 pos2);
diff --git a/src/test/regress/expected/window.out b/src/test/regress/expected/window.out
index 752c7b4..c6f72f8 100644
--- a/src/test/regress/expected/window.out
+++ b/src/test/regress/expected/window.out
@@ -5,19 +5,21 @@ CREATE TEMPORARY TABLE empsalary (
depname varchar,
empno bigint,
salary int,
- enroll_date date
+ enroll_date date,
+ term_date date,
+ respect text
);
INSERT INTO empsalary VALUES
-('develop', 10, 5200, '2007-08-01'),
-('sales', 1, 5000, '2006-10-01'),
-('personnel', 5, 3500, '2007-12-10'),
-('sales', 4, 4800, '2007-08-08'),
-('personnel', 2, 3900, '2006-12-23'),
-('develop', 7, 4200, '2008-01-01'),
-('develop', 9, 4500, '2008-01-01'),
-('sales', 3, 4800, '2007-08-01'),
-('develop', 8, 6000, '2006-10-01'),
-('develop', 11, 5200, '2007-08-15');
+('develop', 10, 5200, '2007-08-01', null, null),
+('sales', 1, 5000, '2006-10-01', null, 'frog'),
+('personnel', 5, 3500, '2007-12-10', null, null),
+('sales', 4, 4800, '2007-08-08', '2010-09-22', 'chicken'),
+('personnel', 2, 3900, '2006-12-23', null, null),
+('develop', 7, 4200, '2008-01-01', null, null),
+('develop', 9, 4500, '2008-01-01', null, 'gorilla'),
+('sales', 3, 4800, '2007-08-01', '2009-03-05', null),
+('develop', 8, 6000, '2006-10-01', '2009-11-17', 'tiger'),
+('develop', 11, 5200, '2007-08-15', null, null);
SELECT depname, empno, salary, sum(salary) OVER (PARTITION BY depname) FROM empsalary ORDER BY depname, salary;
depname | empno | salary | sum
-----------+-------+--------+-------
@@ -989,9 +991,9 @@ ERROR: window functions are not allowed in GROUP BY
LINE 1: SELECT rank() OVER (ORDER BY 1), count(*) FROM empsalary GRO...
^
SELECT * FROM rank() OVER (ORDER BY random());
-ERROR: window functions are not allowed in functions in FROM
+ERROR: syntax error at or near "OVER"
LINE 1: SELECT * FROM rank() OVER (ORDER BY random());
- ^
+ ^
DELETE FROM empsalary WHERE (rank() OVER (ORDER BY random())) > 10;
ERROR: window functions are not allowed in WHERE
LINE 1: DELETE FROM empsalary WHERE (rank() OVER (ORDER BY random())...
@@ -1020,5 +1022,135 @@ SELECT ntile(0) OVER (ORDER BY ten), ten, four FROM tenk1;
ERROR: argument of ntile must be greater than zero
SELECT nth_value(four, 0) OVER (ORDER BY ten), ten, four FROM tenk1;
ERROR: argument of nth_value must be greater than zero
+-- test null behaviour: (1) lags
+SELECT term_date, lag(term_date) OVER (ORDER BY empno) FROM empsalary;
+ term_date | lag
+------------+------------
+ |
+ |
+ 03-05-2009 |
+ 09-22-2010 | 03-05-2009
+ | 09-22-2010
+ |
+ 11-17-2009 |
+ | 11-17-2009
+ |
+ |
+(10 rows)
+
+SELECT term_date, lag(term_date) RESPECT NULLS OVER (ORDER BY empno) FROM empsalary;
+ term_date | lag
+------------+------------
+ |
+ |
+ 03-05-2009 |
+ 09-22-2010 | 03-05-2009
+ | 09-22-2010
+ |
+ 11-17-2009 |
+ | 11-17-2009
+ |
+ |
+(10 rows)
+
+-- a numeric (date) column
+SELECT term_date, lag(term_date) IGNORE NULLS OVER (ORDER BY empno) FROM empsalary;
+ term_date | lag
+------------+------------
+ |
+ |
+ 03-05-2009 |
+ 09-22-2010 | 03-05-2009
+ | 09-22-2010
+ | 09-22-2010
+ 11-17-2009 | 09-22-2010
+ | 11-17-2009
+ | 11-17-2009
+ | 11-17-2009
+(10 rows)
+
+-- a text column
+SELECT respect, lag(respect) IGNORE NULLS OVER (ORDER BY empno) FROM empsalary;
+ respect | lag
+---------+---------
+ frog |
+ | frog
+ | frog
+ chicken | frog
+ | chicken
+ | chicken
+ tiger | chicken
+ gorilla | tiger
+ | gorilla
+ | gorilla
+(10 rows)
+
+-- (2) leads
+SELECT term_date, lead(term_date) OVER (ORDER BY empno) FROM empsalary;
+ term_date | lead
+------------+------------
+ |
+ | 03-05-2009
+ 03-05-2009 | 09-22-2010
+ 09-22-2010 |
+ |
+ | 11-17-2009
+ 11-17-2009 |
+ |
+ |
+ |
+(10 rows)
+
+SELECT term_date, lead(term_date) RESPECT NULLS OVER (ORDER BY empno) FROM empsalary;
+ term_date | lead
+------------+------------
+ |
+ | 03-05-2009
+ 03-05-2009 | 09-22-2010
+ 09-22-2010 |
+ |
+ | 11-17-2009
+ 11-17-2009 |
+ |
+ |
+ |
+(10 rows)
+
+SELECT term_date, lead(term_date) IGNORE NULLS OVER (ORDER BY empno) FROM empsalary;
+ term_date | lead
+------------+------------
+ |
+ | 03-05-2009
+ 03-05-2009 | 09-22-2010
+ 09-22-2010 | 09-22-2010
+ | 09-22-2010
+ | 11-17-2009
+ 11-17-2009 | 11-17-2009
+ | 11-17-2009
+ | 11-17-2009
+ |
+(10 rows)
+
-- cleanup
DROP TABLE empsalary;
+-- some more test cases
+CREATE TABLE test_table (
+ id serial,
+ val integer);
+INSERT INTO test_table (val) SELECT * FROM unnest(ARRAY[1,2,3,4,NULL, NULL, NULL, 5, 6, 7]);
+SELECT val, lead(val, 2) IGNORE NULLS OVER (ORDER BY id) FROM test_table;
+ val | lead
+-----+------
+ 1 | 3
+ 2 | 4
+ 3 | 4
+ 4 | 4
+ | 4
+ | 5
+ | 6
+ 5 | 7
+ 6 |
+ 7 |
+(10 rows)
+
+DROP TABLE test_table;
diff --git a/src/test/regress/sql/window.sql b/src/test/regress/sql/window.sql
index 769be0f..6dba56e 100644
--- a/src/test/regress/sql/window.sql
+++ b/src/test/regress/sql/window.sql
@@ -6,20 +6,22 @@ CREATE TEMPORARY TABLE empsalary (
depname varchar,
empno bigint,
salary int,
- enroll_date date
+ enroll_date date,
+ term_date date,
+ respect text
);
INSERT INTO empsalary VALUES
-('develop', 10, 5200, '2007-08-01'),
-('sales', 1, 5000, '2006-10-01'),
-('personnel', 5, 3500, '2007-12-10'),
-('sales', 4, 4800, '2007-08-08'),
-('personnel', 2, 3900, '2006-12-23'),
-('develop', 7, 4200, '2008-01-01'),
-('develop', 9, 4500, '2008-01-01'),
-('sales', 3, 4800, '2007-08-01'),
-('develop', 8, 6000, '2006-10-01'),
-('develop', 11, 5200, '2007-08-15');
+('develop', 10, 5200, '2007-08-01', null, null),
+('sales', 1, 5000, '2006-10-01', null, 'frog'),
+('personnel', 5, 3500, '2007-12-10', null, null),
+('sales', 4, 4800, '2007-08-08', '2010-09-22', 'chicken'),
+('personnel', 2, 3900, '2006-12-23', null, null),
+('develop', 7, 4200, '2008-01-01', null, null),
+('develop', 9, 4500, '2008-01-01', null, 'gorilla'),
+('sales', 3, 4800, '2007-08-01', '2009-03-05', null),
+('develop', 8, 6000, '2006-10-01', '2009-11-17', 'tiger'),
+('develop', 11, 5200, '2007-08-15', null, null);
SELECT depname, empno, salary, sum(salary) OVER (PARTITION BY depname) FROM empsalary ORDER BY depname, salary;
@@ -264,5 +266,35 @@ SELECT ntile(0) OVER (ORDER BY ten), ten, four FROM tenk1;
SELECT nth_value(four, 0) OVER (ORDER BY ten), ten, four FROM tenk1;
+-- test null behaviour: (1) lags
+
+SELECT term_date, lag(term_date) OVER (ORDER BY empno) FROM empsalary;
+
+SELECT term_date, lag(term_date) RESPECT NULLS OVER (ORDER BY empno) FROM empsalary;
+
+-- a numeric (date) column
+SELECT term_date, lag(term_date) IGNORE NULLS OVER (ORDER BY empno) FROM empsalary;
+
+-- a text column
+SELECT respect, lag(respect) IGNORE NULLS OVER (ORDER BY empno) FROM empsalary;
+
+-- (2) leads
+
+SELECT term_date, lead(term_date) OVER (ORDER BY empno) FROM empsalary;
+
+SELECT term_date, lead(term_date) RESPECT NULLS OVER (ORDER BY empno) FROM empsalary;
+
+SELECT term_date, lead(term_date) IGNORE NULLS OVER (ORDER BY empno) FROM empsalary;
+
-- cleanup
DROP TABLE empsalary;
+
+-- some more test cases
+CREATE TABLE test_table (
+ id serial,
+ val integer);
+INSERT INTO test_table (val) SELECT * FROM unnest(ARRAY[1,2,3,4,NULL, NULL, NULL, 5, 6, 7]);
+
+SELECT val, lead(val, 2) IGNORE NULLS OVER (ORDER BY id) FROM test_table;
+
+DROP TABLE test_table;