Adjust the parser to accept the typename syntax INTERVAL ... SECOND(n)

and the literal syntax INTERVAL 'string' ... SECOND(n), as required by the
SQL standard.  Our old syntax put (n) directly after INTERVAL, which was
a mistake, but will still be accepted for backward compatibility as well
as symmetry with the TIMESTAMP cases.

Change intervaltypmodout to show it in the spec's way, too.  (This could
potentially affect clients, if there are any that analyze the typmod of an
INTERVAL in any detail.)

Also fix interval input to handle 'min:sec.frac' properly; I had overlooked
this case in my previous patch.

Document the use of the interval fields qualifier, which up to now we had
never mentioned in the docs.  (I think the omission was intentional because
it didn't work per spec; but it does now, or at least close enough to be
credible.)

6 files changed, 294 insertions, 56 deletions

diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml
index 48dfe0a9c47..0b969eaa22e 100644
--- a/doc/src/sgml/datatype.sgml
+++ b/doc/src/sgml/datatype.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.227 2008/05/16 16:31:01 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.228 2008/09/11 15:27:30 tgl Exp $ -->
 
  <chapter id="datatype">
   <title id="datatype-title">Data Types</title>
@@ -131,7 +131,7 @@
       </row>
 
       <row>
-       <entry><type>interval [ (<replaceable>p</replaceable>) ]</type></entry>
+       <entry><type>interval [ <replaceable>fields</replaceable> ] [ (<replaceable>p</replaceable>) ]</type></entry>
        <entry></entry>
        <entry>time span</entry>
       </row>
@@ -1420,7 +1420,7 @@ SELECT b, char_length(b) FROM test2;
         <entry>1 microsecond / 14 digits</entry>
        </row>
        <row>
-        <entry><type>interval [ (<replaceable>p</replaceable>) ]</type></entry>
+        <entry><type>interval [ <replaceable>fields</replaceable> ] [ (<replaceable>p</replaceable>) ]</type></entry>
         <entry>12 bytes</entry>
         <entry>time intervals</entry>
         <entry>-178000000 years</entry>
@@ -1506,6 +1506,30 @@ SELECT b, char_length(b) FROM test2;
    </para>
 
    <para>
+    The <type>interval</type> type has an additional option, which is
+    to restrict the set of stored fields by writing one of these phrases:
+<programlisting>
+    YEAR
+    MONTH
+    DAY
+    HOUR
+    MINUTE
+    SECOND
+    YEAR TO MONTH
+    DAY TO HOUR
+    DAY TO MINUTE
+    DAY TO SECOND
+    HOUR TO MINUTE
+    MINUTE TO SECOND
+</programlisting>
+    Input falling outside the specified set of fields is silently discarded.
+    Note that if both <replaceable>fields</replaceable> and
+    <replaceable>precision</replaceable> are specified, the
+    <replaceable>fields</replaceable> must include <literal>SECOND</>,
+    since the precision applies only to the seconds.
+   </para>
+
+   <para>
     The type <type>time with time zone</type> is defined by the SQL
     standard, but the definition exhibits properties which lead to
     questionable usefulness. In most cases, a combination of
@@ -1928,18 +1952,26 @@ January 8 04:05:06 1999 PST
       <replaceable>direction</> can be <literal>ago</literal> or
       empty.  The at sign (<literal>@</>) is optional noise.  The amounts
       of different units are implicitly added up with appropriate
-      sign accounting.
+      sign accounting.  <literal>ago</literal> negates all the fields.
      </para>
 
      <para>
       Quantities of days, hours, minutes, and seconds can be specified without
       explicit unit markings.  For example, <literal>'1 12:59:10'</> is read
-      the same as <literal>'1 day 12 hours 59 min 10 sec'</>.
+      the same as <literal>'1 day 12 hours 59 min 10 sec'</>.  Also,
+      a combination of years and months can be specified with a dash;
+      for example <literal>'200-10'</> is read the same as <literal>'200 years
+      10 months'</>.  (These shorter forms are in fact the only ones allowed
+      by the SQL standard.)
      </para>
 
      <para>
-      The optional subsecond precision <replaceable>p</replaceable> should 
-      be between 0 and 6, and defaults to the precision of the input literal.
+      When writing an interval constant with a <replaceable>fields</>
+      specification, or when assigning to an interval column that was defined
+      with a <replaceable>fields</> specification, the interpretation of
+      unmarked quantities depends on the <replaceable>fields</>.  For
+      example <literal>INTERVAL '1' YEAR</> is read as 1 year, whereas
+      <literal>INTERVAL '1'</> means 1 second.
      </para>
 
      <para>
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 5c716dd8f22..ecbd55d1302 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.622 2008/09/02 20:37:54 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.623 2008/09/11 15:27:30 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -292,7 +292,7 @@ static TypeName *TableFuncTypeName(List *columns);
 
 %type <list>	extract_list overlay_list position_list
 %type <list>	substr_list trim_list
-%type <ival>	opt_interval
+%type <list>	opt_interval interval_second
 %type <node>	overlay_placing substr_from substr_for
 
 %type <boolean> opt_instead opt_analyze
@@ -1222,28 +1222,39 @@ zone_value:
 			| ConstInterval Sconst opt_interval
 				{
 					TypeName *t = $1;
-					if ($3 != INTERVAL_FULL_RANGE)
+					if ($3 != NIL)
 					{
-						if (($3 & ~(INTERVAL_MASK(HOUR) | INTERVAL_MASK(MINUTE))) != 0)
+						A_Const *n = (A_Const *) linitial($3);
+						if ((n->val.val.ival & ~(INTERVAL_MASK(HOUR) | INTERVAL_MASK(MINUTE))) != 0)
 							ereport(ERROR,
 									(errcode(ERRCODE_SYNTAX_ERROR),
 									 errmsg("time zone interval must be HOUR or HOUR TO MINUTE"),
 									 scanner_errposition(@3)));
-						t->typmods = list_make1(makeIntConst($3, @3));
 					}
+					t->typmods = $3;
 					$$ = makeStringConstCast($2, @2, t);
 				}
 			| ConstInterval '(' Iconst ')' Sconst opt_interval
 				{
 					TypeName *t = $1;
-					if (($6 != INTERVAL_FULL_RANGE)
-						&& (($6 & ~(INTERVAL_MASK(HOUR) | INTERVAL_MASK(MINUTE))) != 0))
-						ereport(ERROR,
-								(errcode(ERRCODE_SYNTAX_ERROR),
-								 errmsg("time zone interval must be HOUR or HOUR TO MINUTE"),
-								 scanner_errposition(@6)));
-					t->typmods = list_make2(makeIntConst($6, @6),
-											makeIntConst($3, @3));
+					if ($6 != NIL)
+					{
+						A_Const *n = (A_Const *) linitial($6);
+						if ((n->val.val.ival & ~(INTERVAL_MASK(HOUR) | INTERVAL_MASK(MINUTE))) != 0)
+							ereport(ERROR,
+									(errcode(ERRCODE_SYNTAX_ERROR),
+									 errmsg("time zone interval must be HOUR or HOUR TO MINUTE"),
+									 scanner_errposition(@6)));
+						if (list_length($6) != 1)
+							ereport(ERROR,
+									(errcode(ERRCODE_SYNTAX_ERROR),
+									 errmsg("interval precision specified twice"),
+									 scanner_errposition(@1)));
+						t->typmods = lappend($6, makeIntConst($3, @3));
+					}
+					else
+						t->typmods = list_make2(makeIntConst(INTERVAL_FULL_RANGE, -1),
+												makeIntConst($3, @3));
 					$$ = makeStringConstCast($5, @5, t);
 				}
 			| NumericOnly							{ $$ = makeAConst($1, @1); }
@@ -6983,14 +6994,23 @@ SimpleTypename:
 			| ConstInterval opt_interval
 				{
 					$$ = $1;
-					if ($2 != INTERVAL_FULL_RANGE)
-						$$->typmods = list_make1(makeIntConst($2, @2));
+					$$->typmods = $2;
 				}
 			| ConstInterval '(' Iconst ')' opt_interval
 				{
 					$$ = $1;
-					$$->typmods = list_make2(makeIntConst($5, @5),
-											 makeIntConst($3, @3));
+					if ($5 != NIL)
+					{
+						if (list_length($5) != 1)
+							ereport(ERROR,
+									(errcode(ERRCODE_SYNTAX_ERROR),
+									 errmsg("interval precision specified twice"),
+									 scanner_errposition(@1)));
+						$$->typmods = lappend($5, makeIntConst($3, @3));
+					}
+					else
+						$$->typmods = list_make2(makeIntConst(INTERVAL_FULL_RANGE, -1),
+												 makeIntConst($3, @3));
 				}
 		;
 
@@ -7337,30 +7357,74 @@ opt_timezone:
 		;
 
 opt_interval:
-			YEAR_P									{ $$ = INTERVAL_MASK(YEAR); }
-			| MONTH_P								{ $$ = INTERVAL_MASK(MONTH); }
-			| DAY_P									{ $$ = INTERVAL_MASK(DAY); }
-			| HOUR_P								{ $$ = INTERVAL_MASK(HOUR); }
-			| MINUTE_P								{ $$ = INTERVAL_MASK(MINUTE); }
-			| SECOND_P								{ $$ = INTERVAL_MASK(SECOND); }
+			YEAR_P
+				{ $$ = list_make1(makeIntConst(INTERVAL_MASK(YEAR), @1)); }
+			| MONTH_P
+				{ $$ = list_make1(makeIntConst(INTERVAL_MASK(MONTH), @1)); }
+			| DAY_P
+				{ $$ = list_make1(makeIntConst(INTERVAL_MASK(DAY), @1)); }
+			| HOUR_P
+				{ $$ = list_make1(makeIntConst(INTERVAL_MASK(HOUR), @1)); }
+			| MINUTE_P
+				{ $$ = list_make1(makeIntConst(INTERVAL_MASK(MINUTE), @1)); }
+			| interval_second
+				{ $$ = $1; }
 			| YEAR_P TO MONTH_P
-					{ $$ = INTERVAL_MASK(YEAR) | INTERVAL_MASK(MONTH); }
+				{
+					$$ = list_make1(makeIntConst(INTERVAL_MASK(YEAR) |
+												 INTERVAL_MASK(MONTH), @1));
+				}
 			| DAY_P TO HOUR_P
-					{ $$ = INTERVAL_MASK(DAY) | INTERVAL_MASK(HOUR); }
+				{
+					$$ = list_make1(makeIntConst(INTERVAL_MASK(DAY) |
+												 INTERVAL_MASK(HOUR), @1));
+				}
 			| DAY_P TO MINUTE_P
-					{ $$ = INTERVAL_MASK(DAY) | INTERVAL_MASK(HOUR)
-						| INTERVAL_MASK(MINUTE); }
-			| DAY_P TO SECOND_P
-					{ $$ = INTERVAL_MASK(DAY) | INTERVAL_MASK(HOUR)
-						| INTERVAL_MASK(MINUTE) | INTERVAL_MASK(SECOND); }
+				{
+					$$ = list_make1(makeIntConst(INTERVAL_MASK(DAY) |
+												 INTERVAL_MASK(HOUR) |
+												 INTERVAL_MASK(MINUTE), @1));
+				}
+			| DAY_P TO interval_second
+				{
+					$$ = $3;
+					linitial($$) = makeIntConst(INTERVAL_MASK(DAY) |
+												INTERVAL_MASK(HOUR) |
+												INTERVAL_MASK(MINUTE) |
+												INTERVAL_MASK(SECOND), @1);
+				}
 			| HOUR_P TO MINUTE_P
-					{ $$ = INTERVAL_MASK(HOUR) | INTERVAL_MASK(MINUTE); }
-			| HOUR_P TO SECOND_P
-					{ $$ = INTERVAL_MASK(HOUR) | INTERVAL_MASK(MINUTE)
-						| INTERVAL_MASK(SECOND); }
-			| MINUTE_P TO SECOND_P
-					{ $$ = INTERVAL_MASK(MINUTE) | INTERVAL_MASK(SECOND); }
-			| /*EMPTY*/								{ $$ = INTERVAL_FULL_RANGE; }
+				{
+					$$ = list_make1(makeIntConst(INTERVAL_MASK(HOUR) |
+												 INTERVAL_MASK(MINUTE), @1));
+				}
+			| HOUR_P TO interval_second
+				{
+					$$ = $3;
+					linitial($$) = makeIntConst(INTERVAL_MASK(HOUR) |
+												INTERVAL_MASK(MINUTE) |
+												INTERVAL_MASK(SECOND), @1);
+				}
+			| MINUTE_P TO interval_second
+				{
+					$$ = $3;
+					linitial($$) = makeIntConst(INTERVAL_MASK(MINUTE) |
+												INTERVAL_MASK(SECOND), @1);
+				}
+			| /*EMPTY*/
+				{ $$ = NIL; }
+		;
+
+interval_second:
+			SECOND_P
+				{
+					$$ = list_make1(makeIntConst(INTERVAL_MASK(SECOND), @1));
+				}
+			| SECOND_P '(' Iconst ')'
+				{
+					$$ = list_make2(makeIntConst(INTERVAL_MASK(SECOND), @1),
+									makeIntConst($3, @3));
+				}
 		;
 
 
@@ -9014,16 +9078,24 @@ AexprConst: Iconst
 			| ConstInterval Sconst opt_interval
 				{
 					TypeName *t = $1;
-					/* precision is not specified, but fields may be... */
-					if ($3 != INTERVAL_FULL_RANGE)
-						t->typmods = list_make1(makeIntConst($3, @3));
+					t->typmods = $3;
 					$$ = makeStringConstCast($2, @2, t);
 				}
 			| ConstInterval '(' Iconst ')' Sconst opt_interval
 				{
 					TypeName *t = $1;
-					t->typmods = list_make2(makeIntConst($6, @6),
-										    makeIntConst($3, @3));
+					if ($6 != NIL)
+					{
+						if (list_length($6) != 1)
+							ereport(ERROR,
+									(errcode(ERRCODE_SYNTAX_ERROR),
+									 errmsg("interval precision specified twice"),
+									 scanner_errposition(@1)));
+						t->typmods = lappend($6, makeIntConst($3, @3));
+					}
+					else
+						t->typmods = list_make2(makeIntConst(INTERVAL_FULL_RANGE, -1),
+												makeIntConst($3, @3));
 					$$ = makeStringConstCast($5, @5, t);
 				}
 			| TRUE_P
diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
index 6712d6d8d44..a1cf2b4ed54 100644
--- a/src/backend/utils/adt/datetime.c
+++ b/src/backend/utils/adt/datetime.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.191 2008/09/10 18:29:41 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.192 2008/09/11 15:27:30 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2256,9 +2256,25 @@ DecodeTime(char *str, int fmask, int range,
 			tm->tm_hour = 0;
 		}
 	}
-	else if (*cp != ':')
-		return DTERR_BAD_FORMAT;
-	else
+	else if (*cp == '.')
+	{
+		/* always assume mm:ss.sss is MINUTE TO SECOND */
+		double		frac;
+
+		str = cp;
+		frac = strtod(str, &cp);
+		if (*cp != '\0')
+			return DTERR_BAD_FORMAT;
+#ifdef HAVE_INT64_TIMESTAMP
+		*fsec = rint(frac * 1000000);
+#else
+		*fsec = frac;
+#endif
+		tm->tm_sec = tm->tm_min;
+		tm->tm_min = tm->tm_hour;
+		tm->tm_hour = 0;
+	}
+	else if (*cp == ':')
 	{
 		str = cp + 1;
 		errno = 0;
@@ -2284,6 +2300,8 @@ DecodeTime(char *str, int fmask, int range,
 		else
 			return DTERR_BAD_FORMAT;
 	}
+	else
+		return DTERR_BAD_FORMAT;
 
 	/* do a sanity check */
 #ifdef HAVE_INT64_TIMESTAMP
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 9060b989f9c..acfc89ba047 100644
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.191 2008/09/10 18:29:41 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.192 2008/09/11 15:27:30 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -744,7 +744,7 @@ intervaltypmodin(PG_FUNCTION_ARGS)
 	tl = ArrayGetIntegerTypmods(ta, &n);
 
 	/*
-	 * tl[0] - opt_interval tl[1] - Iconst (optional)
+	 * tl[0] - interval range (fields bitmask)  tl[1] - precision (optional)
 	 *
 	 * Note we must validate tl[0] even though it's normally guaranteed
 	 * correct by the grammar --- consider SELECT 'foo'::"interval"(1000).
@@ -881,7 +881,7 @@ intervaltypmodout(PG_FUNCTION_ARGS)
 	}
 
 	if (precision != INTERVAL_FULL_PRECISION)
-		snprintf(res, 64, "(%d)%s", precision, fieldstr);
+		snprintf(res, 64, "%s(%d)", fieldstr, precision);
 	else
 		snprintf(res, 64, "%s", fieldstr);
 
diff --git a/src/test/regress/expected/interval.out b/src/test/regress/expected/interval.out
index ede3c58708c..a9b5766439b 100644
--- a/src/test/regress/expected/interval.out
+++ b/src/test/regress/expected/interval.out
@@ -518,3 +518,100 @@ SELECT interval '1 2:03:04' minute to second;
  00:03:04
 (1 row)
 
+-- test syntaxes for restricted precision
+SELECT interval(0) '1 day 01:23:45.6789';
+    interval    
+----------------
+ 1 day 01:23:46
+(1 row)
+
+SELECT interval(2) '1 day 01:23:45.6789';
+     interval      
+-------------------
+ 1 day 01:23:45.68
+(1 row)
+
+SELECT interval '12:34.5678' minute to second(2);  -- per SQL spec
+  interval   
+-------------
+ 00:12:34.57
+(1 row)
+
+SELECT interval(2) '12:34.5678' minute to second;  -- historical PG
+  interval   
+-------------
+ 00:12:34.57
+(1 row)
+
+SELECT interval(2) '12:34.5678' minute to second(2);  -- syntax error
+ERROR:  interval precision specified twice
+LINE 1: SELECT interval(2) '12:34.5678' minute to second(2);
+               ^
+SELECT interval '1.234' second;
+   interval   
+--------------
+ 00:00:01.234
+(1 row)
+
+SELECT interval '1.234' second(2);
+  interval   
+-------------
+ 00:00:01.23
+(1 row)
+
+SELECT interval '1 2.345' day to second(2);
+    interval    
+----------------
+ 1 day 02:20:42
+(1 row)
+
+SELECT interval '1 2:03' day to second(2);
+    interval    
+----------------
+ 1 day 02:03:00
+(1 row)
+
+SELECT interval '1 2:03.4567' day to second(2);
+     interval      
+-------------------
+ 1 day 00:02:03.46
+(1 row)
+
+SELECT interval '1 2:03:04.5678' day to second(2);
+     interval      
+-------------------
+ 1 day 02:03:04.57
+(1 row)
+
+SELECT interval '1 2.345' hour to second(2);
+ERROR:  invalid input syntax for type interval: "1 2.345"
+LINE 1: SELECT interval '1 2.345' hour to second(2);
+                        ^
+SELECT interval '1 2:03.45678' hour to second(2);
+  interval   
+-------------
+ 00:02:03.46
+(1 row)
+
+SELECT interval '1 2:03:04.5678' hour to second(2);
+  interval   
+-------------
+ 02:03:04.57
+(1 row)
+
+SELECT interval '1 2.3456' minute to second(2);
+ERROR:  invalid input syntax for type interval: "1 2.3456"
+LINE 1: SELECT interval '1 2.3456' minute to second(2);
+                        ^
+SELECT interval '1 2:03.5678' minute to second(2);
+  interval   
+-------------
+ 00:02:03.57
+(1 row)
+
+SELECT interval '1 2:03:04.5678' minute to second(2);
+  interval   
+-------------
+ 00:03:04.57
+(1 row)
+
diff --git a/src/test/regress/sql/interval.sql b/src/test/regress/sql/interval.sql
index 2c6aecaa519..06e47058591 100644
--- a/src/test/regress/sql/interval.sql
+++ b/src/test/regress/sql/interval.sql
@@ -156,3 +156,22 @@ SELECT interval '1 2:03:04' hour to second;
 SELECT interval '1 2' minute to second;
 SELECT interval '1 2:03' minute to second;
 SELECT interval '1 2:03:04' minute to second;
+
+-- test syntaxes for restricted precision
+SELECT interval(0) '1 day 01:23:45.6789';
+SELECT interval(2) '1 day 01:23:45.6789';
+SELECT interval '12:34.5678' minute to second(2);  -- per SQL spec
+SELECT interval(2) '12:34.5678' minute to second;  -- historical PG
+SELECT interval(2) '12:34.5678' minute to second(2);  -- syntax error
+SELECT interval '1.234' second;
+SELECT interval '1.234' second(2);
+SELECT interval '1 2.345' day to second(2);
+SELECT interval '1 2:03' day to second(2);
+SELECT interval '1 2:03.4567' day to second(2);
+SELECT interval '1 2:03:04.5678' day to second(2);
+SELECT interval '1 2.345' hour to second(2);
+SELECT interval '1 2:03.45678' hour to second(2);
+SELECT interval '1 2:03:04.5678' hour to second(2);
+SELECT interval '1 2.3456' minute to second(2);
+SELECT interval '1 2:03.5678' minute to second(2);
+SELECT interval '1 2:03:04.5678' minute to second(2);