</para></entry>
</row>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>random</primary>
+ </indexterm>
+ <function>random</function> ( <parameter>min</parameter> <type>date</type>, <parameter>max</parameter> <type>date</type> )
+ <returnvalue>date</returnvalue>
+ </para>
+ <para role="func_signature">
+ <function>random</function> ( <parameter>min</parameter> <type>timestamp</type>, <parameter>max</parameter> <type>timestamp</type> )
+ <returnvalue>timestamp</returnvalue>
+ </para>
+ <para role="func_signature">
+ <function>random</function> ( <parameter>min</parameter> <type>timestamptz</type>, <parameter>max</parameter> <type>timestamptz</type> )
+ <returnvalue>timestamptz</returnvalue>
+ </para>
+ <para>
+ Returns a random value in the range
+ <parameter>min</parameter> <= x <= <parameter>max</parameter>.
+ </para>
+ <para>
+ <literal>random('1979-02-08'::date,'2025-07-03'::date)</literal>
+ <returnvalue>1983-04-21</returnvalue>
+ </para>
+ <para>
+ <literal>random('2000-01-01'::timestamptz, now())</literal>
+ <returnvalue>2015-09-27 09:11:33.732707+00</returnvalue>
+ </para></entry>
+ </row>
+
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
<para>
The <function>random()</function> and <function>random_normal()</function>
- functions listed in <xref linkend="functions-math-random-table"/> use a
+ functions listed in <xref linkend="functions-math-random-table"/> and
+ <xref linkend="functions-datetime-table"/> use a
deterministic pseudo-random number generator.
It is fast but not suitable for cryptographic
applications; see the <xref linkend="pgcrypto"/> module for a more
#include "common/pg_prng.h"
#include "miscadmin.h"
+#include "utils/date.h"
#include "utils/fmgrprotos.h"
#include "utils/numeric.h"
#include "utils/timestamp.h"
static pg_prng_state prng_state;
static bool prng_seed_set = false;
+/*
+ * Macro for checking the range bounds of random(min, max) functions. Throws
+ * an error if they're the wrong way round.
+ */
+#define CHECK_RANGE_BOUNDS(rmin, rmax) \
+ do { \
+ if ((rmin) > (rmax)) \
+ ereport(ERROR, \
+ errcode(ERRCODE_INVALID_PARAMETER_VALUE), \
+ errmsg("lower bound must be less than or equal to upper bound")); \
+ } while (0)
+
/*
* initialize_prng() -
*
int32 rmax = PG_GETARG_INT32(1);
int32 result;
- if (rmin > rmax)
- ereport(ERROR,
- errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("lower bound must be less than or equal to upper bound"));
+ CHECK_RANGE_BOUNDS(rmin, rmax);
initialize_prng();
int64 rmax = PG_GETARG_INT64(1);
int64 result;
- if (rmin > rmax)
- ereport(ERROR,
- errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("lower bound must be less than or equal to upper bound"));
+ CHECK_RANGE_BOUNDS(rmin, rmax);
initialize_prng();
Numeric rmax = PG_GETARG_NUMERIC(1);
Numeric result;
+ /* Leave range bound checking to random_numeric() */
+
initialize_prng();
result = random_numeric(&prng_state, rmin, rmax);
PG_RETURN_NUMERIC(result);
}
+
+
+/*
+ * date_random() -
+ *
+ * Returns a random date chosen uniformly in the specified range.
+ */
+Datum
+date_random(PG_FUNCTION_ARGS)
+{
+ int32 rmin = (int32) PG_GETARG_DATEADT(0);
+ int32 rmax = (int32) PG_GETARG_DATEADT(1);
+ DateADT result;
+
+ CHECK_RANGE_BOUNDS(rmin, rmax);
+
+ if (DATE_IS_NOBEGIN(rmin) || DATE_IS_NOEND(rmax))
+ ereport(ERROR,
+ errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("lower and upper bounds must be finite"));
+
+ initialize_prng();
+
+ result = (DateADT) pg_prng_int64_range(&prng_state, rmin, rmax);
+
+ PG_RETURN_DATEADT(result);
+}
+
+/*
+ * timestamp_random() -
+ *
+ * Returns a random timestamp chosen uniformly in the specified range.
+ */
+Datum
+timestamp_random(PG_FUNCTION_ARGS)
+{
+ int64 rmin = (int64) PG_GETARG_TIMESTAMP(0);
+ int64 rmax = (int64) PG_GETARG_TIMESTAMP(1);
+ Timestamp result;
+
+ CHECK_RANGE_BOUNDS(rmin, rmax);
+
+ if (TIMESTAMP_IS_NOBEGIN(rmin) || TIMESTAMP_IS_NOEND(rmax))
+ ereport(ERROR,
+ errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("lower and upper bounds must be finite"));
+
+ initialize_prng();
+
+ result = (Timestamp) pg_prng_int64_range(&prng_state, rmin, rmax);
+
+ PG_RETURN_TIMESTAMP(result);
+}
+
+/*
+ * timestamptz_random() -
+ *
+ * Returns a random timestamptz chosen uniformly in the specified range.
+ */
+Datum
+timestamptz_random(PG_FUNCTION_ARGS)
+{
+ int64 rmin = (int64) PG_GETARG_TIMESTAMPTZ(0);
+ int64 rmax = (int64) PG_GETARG_TIMESTAMPTZ(1);
+ TimestampTz result;
+
+ CHECK_RANGE_BOUNDS(rmin, rmax);
+
+ if (TIMESTAMP_IS_NOBEGIN(rmin) || TIMESTAMP_IS_NOEND(rmax))
+ ereport(ERROR,
+ errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("lower and upper bounds must be finite"));
+
+ initialize_prng();
+
+ result = (TimestampTz) pg_prng_int64_range(&prng_state, rmin, rmax);
+
+ PG_RETURN_TIMESTAMPTZ(result);
+}
*/
/* yyyymmddN */
-#define CATALOG_VERSION_NO 202509021
+#define CATALOG_VERSION_NO 202509091
#endif
proname => 'random', provolatile => 'v', proparallel => 'r',
prorettype => 'numeric', proargtypes => 'numeric numeric',
proargnames => '{min,max}', prosrc => 'numeric_random' },
+{ oid => '6431', descr => 'random date in range',
+ proname => 'random', provolatile => 'v', proparallel => 'r',
+ prorettype => 'date', proargtypes => 'date date',
+ proargnames => '{min,max}', prosrc => 'date_random' },
+{ oid => '6432', descr => 'random timestamp in range',
+ proname => 'random', provolatile => 'v', proparallel => 'r',
+ prorettype => 'timestamp', proargtypes => 'timestamp timestamp',
+ proargnames => '{min,max}', prosrc => 'timestamp_random' },
+{ oid => '6433', descr => 'random timestamptz in range',
+ proname => 'random', provolatile => 'v', proparallel => 'r',
+ prorettype => 'timestamptz', proargtypes => 'timestamptz timestamptz',
+ proargnames => '{min,max}', prosrc => 'timestamptz_random' },
{ oid => '1599', descr => 'set random seed',
proname => 'setseed', provolatile => 'v', proparallel => 'r',
prorettype => 'void', proargtypes => 'float8', prosrc => 'setseed' },
20 | 0.60795101234744211935
(41 rows)
+-- random dates
+SELECT random('1979-02-08'::date,'2025-07-03'::date) AS random_date_multiple_years;
+ random_date_multiple_years
+----------------------------
+ 04-09-1986
+(1 row)
+
+SELECT random('4714-11-24 BC'::date,'5874897-12-31 AD'::date) AS random_date_maximum_range;
+ random_date_maximum_range
+---------------------------
+ 10-02-2898131
+(1 row)
+
+SELECT random('1979-02-08'::date,'1979-02-08'::date) AS random_date_empty_range;
+ random_date_empty_range
+-------------------------
+ 02-08-1979
+(1 row)
+
+SELECT random('2024-12-31'::date, '2024-01-01'::date); -- fail
+ERROR: lower bound must be less than or equal to upper bound
+SELECT random('-infinity'::date, '2024-01-01'::date); -- fail
+ERROR: lower and upper bounds must be finite
+SELECT random('2024-12-31'::date, 'infinity'::date); -- fail
+ERROR: lower and upper bounds must be finite
+-- random timestamps
+SELECT random('1979-02-08'::timestamp,'2025-07-03'::timestamp) AS random_timestamp_multiple_years;
+ random_timestamp_multiple_years
+---------------------------------
+ Fri Jan 27 18:52:05.366009 2017
+(1 row)
+
+SELECT random('4714-11-24 BC'::timestamp,'294276-12-31 23:59:59.999999'::timestamp) AS random_timestamp_maximum_range;
+ random_timestamp_maximum_range
+-----------------------------------
+ Wed Mar 28 00:45:36.180395 226694
+(1 row)
+
+SELECT random('2024-07-01 12:00:00.000001'::timestamp, '2024-07-01 12:00:00.999999'::timestamp) AS random_narrow_range;
+ random_narrow_range
+---------------------------------
+ Mon Jul 01 12:00:00.999286 2024
+(1 row)
+
+SELECT random('1979-02-08'::timestamp,'1979-02-08'::timestamp) AS random_timestamp_empty_range;
+ random_timestamp_empty_range
+------------------------------
+ Thu Feb 08 00:00:00 1979
+(1 row)
+
+SELECT random('2024-12-31'::timestamp, '2024-01-01'::timestamp); -- fail
+ERROR: lower bound must be less than or equal to upper bound
+SELECT random('-infinity'::timestamp, '2024-01-01'::timestamp); -- fail
+ERROR: lower and upper bounds must be finite
+SELECT random('2024-12-31'::timestamp, 'infinity'::timestamp); -- fail
+ERROR: lower and upper bounds must be finite
+-- random timestamps with timezone
+SELECT random('1979-02-08 +01'::timestamptz,'2025-07-03 +02'::timestamptz) AS random_timestamptz_multiple_years;
+ random_timestamptz_multiple_years
+-------------------------------------
+ Tue Jun 14 04:41:16.652896 2016 PDT
+(1 row)
+
+SELECT random('4714-11-24 BC +00'::timestamptz,'294276-12-31 23:59:59.999999 +00'::timestamptz) AS random_timestamptz_maximum_range;
+ random_timestamptz_maximum_range
+--------------------------------------
+ Wed Mar 26 14:07:16.980265 31603 PDT
+(1 row)
+
+SELECT random('2024-07-01 12:00:00.000001 +04'::timestamptz, '2024-07-01 12:00:00.999999 +04'::timestamptz) AS random_timestamptz_narrow_range;
+ random_timestamptz_narrow_range
+-------------------------------------
+ Mon Jul 01 01:00:00.835808 2024 PDT
+(1 row)
+
+SELECT random('1979-02-08 +05'::timestamptz,'1979-02-08 +05'::timestamptz) AS random_timestamptz_empty_range;
+ random_timestamptz_empty_range
+--------------------------------
+ Wed Feb 07 11:00:00 1979 PST
+(1 row)
+
+SELECT random('2024-01-01 +06'::timestamptz, '2024-01-01 +07'::timestamptz); -- fail
+ERROR: lower bound must be less than or equal to upper bound
+SELECT random('-infinity'::timestamptz, '2024-01-01 +07'::timestamptz); -- fail
+ERROR: lower and upper bounds must be finite
+SELECT random('2024-01-01 +06'::timestamptz, 'infinity'::timestamptz); -- fail
+ERROR: lower and upper bounds must be finite
SELECT random(-0.4, 0.4) FROM generate_series(1, 10);
SELECT random(0, 1 - 1e-30) FROM generate_series(1, 10);
SELECT n, random(0, trim_scale(abs(1 - 10.0^(-n)))) FROM generate_series(-20, 20) n;
+
+-- random dates
+SELECT random('1979-02-08'::date,'2025-07-03'::date) AS random_date_multiple_years;
+SELECT random('4714-11-24 BC'::date,'5874897-12-31 AD'::date) AS random_date_maximum_range;
+SELECT random('1979-02-08'::date,'1979-02-08'::date) AS random_date_empty_range;
+SELECT random('2024-12-31'::date, '2024-01-01'::date); -- fail
+SELECT random('-infinity'::date, '2024-01-01'::date); -- fail
+SELECT random('2024-12-31'::date, 'infinity'::date); -- fail
+
+-- random timestamps
+SELECT random('1979-02-08'::timestamp,'2025-07-03'::timestamp) AS random_timestamp_multiple_years;
+SELECT random('4714-11-24 BC'::timestamp,'294276-12-31 23:59:59.999999'::timestamp) AS random_timestamp_maximum_range;
+SELECT random('2024-07-01 12:00:00.000001'::timestamp, '2024-07-01 12:00:00.999999'::timestamp) AS random_narrow_range;
+SELECT random('1979-02-08'::timestamp,'1979-02-08'::timestamp) AS random_timestamp_empty_range;
+SELECT random('2024-12-31'::timestamp, '2024-01-01'::timestamp); -- fail
+SELECT random('-infinity'::timestamp, '2024-01-01'::timestamp); -- fail
+SELECT random('2024-12-31'::timestamp, 'infinity'::timestamp); -- fail
+
+-- random timestamps with timezone
+SELECT random('1979-02-08 +01'::timestamptz,'2025-07-03 +02'::timestamptz) AS random_timestamptz_multiple_years;
+SELECT random('4714-11-24 BC +00'::timestamptz,'294276-12-31 23:59:59.999999 +00'::timestamptz) AS random_timestamptz_maximum_range;
+SELECT random('2024-07-01 12:00:00.000001 +04'::timestamptz, '2024-07-01 12:00:00.999999 +04'::timestamptz) AS random_timestamptz_narrow_range;
+SELECT random('1979-02-08 +05'::timestamptz,'1979-02-08 +05'::timestamptz) AS random_timestamptz_empty_range;
+SELECT random('2024-01-01 +06'::timestamptz, '2024-01-01 +07'::timestamptz); -- fail
+SELECT random('-infinity'::timestamptz, '2024-01-01 +07'::timestamptz); -- fail
+SELECT random('2024-01-01 +06'::timestamptz, 'infinity'::timestamptz); -- fail
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