generate_series()
function in PostgreSQL is a set-returning function that generates a series of values, based on the start and end values defined by the user. It is useful for generating test data or for creating a sequence of numbers or timestamps.
generate_series()
function is as follows:
start
, stop
, and step
can be of type integer
, bigint
, numeric
, or timestamp
.
start
is the first value in the series.stop
is the last value in the series.step
is optional unless start
and stop
are of type timestamp
. It is the increment value. If it is omitted, the default step value is 1.generate_series()
function to generate a series of numbers:
generate_series()
function to generate a series of timestamps:
now()
as the stop
parameter in the generate_series()
function. For example:
start
must be a constant expression of type timestamptz.stop
must be now()
.step
must be a constant expression of type interval.range()
function in PostgreSQL is a set-returning function that generates a series of values, based on the start and end values defined by the user. The end value is not included, unlike generate_series()
. It is useful for generating test data or for creating a sequence of numbers or timestamps.
The syntax for the range()
function is as follows:
start
, stop
, and step
can be of type integer
, bigint
, numeric
, or `timestamp.
start
is the first value in the series.stop
is the last value in the series.step
is optional unless start
and stop
are of type timestamp
. It is the increment value. If it is omitted, the default step value is 1.range()
function to generate a series of numbers:
range()
function to generate a series of timestamps:
_pg_expandarray
function takes an array as input and expands it into a set of rows, providing values and their corresponding indices within the array. Ensure that information_schema
is in the search path to access the _pg_expandarray
function.
Example: