diff options
Diffstat (limited to 'src/backend/utils/adt/timestamp.c')
| -rw-r--r-- | src/backend/utils/adt/timestamp.c | 92 |
1 files changed, 86 insertions, 6 deletions
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c index b4736dd6ae..0730d56147 100644 --- a/src/backend/utils/adt/timestamp.c +++ b/src/backend/utils/adt/timestamp.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/utils/adt/timestamp.c,v 1.33 2000/07/12 22:59:09 petere Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/adt/timestamp.c,v 1.34 2000/07/17 03:05:18 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -29,6 +29,7 @@ #include "access/hash.h" #include "access/xact.h" #include "miscadmin.h" +#include "utils/array.h" #include "utils/builtins.h" @@ -882,10 +883,6 @@ overlaps_timestamp(PG_FUNCTION_ARGS) /*---------------------------------------------------------- * "Arithmetic" operators on date/times. - * timestamp_foo returns foo as an object (pointer) that - * can be passed between languages. - * timestamp_xx is an internal routine which returns the - * actual value. *---------------------------------------------------------*/ Datum @@ -1150,7 +1147,6 @@ interval_larger(PG_FUNCTION_ARGS) PG_RETURN_INTERVAL_P(result); } - Datum interval_pl(PG_FUNCTION_ARGS) { @@ -1232,6 +1228,90 @@ interval_div(PG_FUNCTION_ARGS) PG_RETURN_INTERVAL_P(result); } +/* + * interval_accum and interval_avg implement the AVG(interval) aggregate. + * + * The transition datatype for this aggregate is a 2-element array of + * intervals, where the first is the running sum and the second contains + * the number of values so far in its 'time' field. This is a bit ugly + * but it beats inventing a specialized datatype for the purpose. + */ + +Datum +interval_accum(PG_FUNCTION_ARGS) +{ + ArrayType *transarray = PG_GETARG_ARRAYTYPE_P(0); + Interval *newval = PG_GETARG_INTERVAL_P(1); + Datum *transdatums; + int ndatums; + Interval sumX, + N; + Interval *newsum; + ArrayType *result; + + /* We assume the input is array of interval */ + deconstruct_array(transarray, + false, 12, 'd', + &transdatums, &ndatums); + if (ndatums != 2) + elog(ERROR, "interval_accum: expected 2-element interval array"); + /* + * XXX memcpy, instead of just extracting a pointer, to work around + * buggy array code: it won't ensure proper alignment of Interval + * objects on machines where double requires 8-byte alignment. + * That should be fixed, but in the meantime... + */ + memcpy(&sumX, DatumGetIntervalP(transdatums[0]), sizeof(Interval)); + memcpy(&N, DatumGetIntervalP(transdatums[1]), sizeof(Interval)); + + newsum = DatumGetIntervalP(DirectFunctionCall2(interval_pl, + IntervalPGetDatum(&sumX), + IntervalPGetDatum(newval))); + N.time += 1; + + transdatums[0] = IntervalPGetDatum(newsum); + transdatums[1] = IntervalPGetDatum(&N); + + result = construct_array(transdatums, 2, + false, 12, 'd'); + + PG_RETURN_ARRAYTYPE_P(result); +} + +Datum +interval_avg(PG_FUNCTION_ARGS) +{ + ArrayType *transarray = PG_GETARG_ARRAYTYPE_P(0); + Datum *transdatums; + int ndatums; + Interval sumX, + N; + + /* We assume the input is array of interval */ + deconstruct_array(transarray, + false, 12, 'd', + &transdatums, &ndatums); + if (ndatums != 2) + elog(ERROR, "interval_avg: expected 2-element interval array"); + /* + * XXX memcpy, instead of just extracting a pointer, to work around + * buggy array code: it won't ensure proper alignment of Interval + * objects on machines where double requires 8-byte alignment. + * That should be fixed, but in the meantime... + */ + memcpy(&sumX, DatumGetIntervalP(transdatums[0]), sizeof(Interval)); + memcpy(&N, DatumGetIntervalP(transdatums[1]), sizeof(Interval)); + + /* SQL92 defines AVG of no values to be NULL */ + if (N.time == 0) + PG_RETURN_NULL(); + + return DirectFunctionCall2(interval_div, + IntervalPGetDatum(&sumX), + Float8GetDatum(N.time)); +} + + /* timestamp_age() * Calculate time difference while retaining year/month fields. * Note that this does not result in an accurate absolute time span |