Postgres 仿oracle的nvl函数

Postgres 仿oracle的nvl函数

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调用方式select nvl(null,'aaa'),nvl(null,now())

以下代码只提供以上几个函数，如果需要更多类型，可按此方法增加其他数据类型的nvl函数

自定义函数

CREATE OR REPLACE FUNCTION nvl(character varying, character varying)

RETURNS character varying AS

$BODY$

declare

begin

if $1 is not null then

return $1;

else

return $2;

end if;

end;

$BODY$

LANGUAGE 'plpgsql' VOLATILE

COST 100;

CREATE OR REPLACE FUNCTION nvl(boolean, boolean)

RETURNS boolean AS

$BODY$

declare

begin

if $1 is not null then

return $1;

else

return $2;

end if;

end;

$BODY$

LANGUAGE 'plpgsql' VOLATILE

COST 100;

CREATE OR REPLACE FUNCTION nvl(interval, interval)

RETURNS interval AS

$BODY$

declare

begin

if $1 is not null then

return $1;

else

return $2;

end if;

end;

$BODY$

LANGUAGE 'plpgsql' VOLATILE

COST 100;

CREATE OR REPLACE FUNCTION nvl(time without time zone, time without time zone)

RETURNS time without time zone AS

$BODY$

declare

begin

if $1 is not null then

return $1;

else

return $2;

end if;

end;

$BODY$

LANGUAGE 'plpgsql' VOLATILE

COST 100;

CREATE OR REPLACE FUNCTION nvl(date, date)

RETURNS date AS

$BODY$

declare

begin

if $1 is not null then

return $1;

else

return $2;

end if;

end;

$BODY$

LANGUAGE 'plpgsql' VOLATILE

COST 100;

CREATE OR REPLACE FUNCTION nvl(numeric, numeric)

RETURNS numeric AS

$BODY$

declare

begin

if $1 is not null then

return $1;

else

return $2;

end if;

end;

$BODY$

LANGUAGE 'plpgsql' VOLATILE

COST 100;

CREATE OR REPLACE FUNCTION nvl(timestamp without time zone, timestamp without time zone)

RETURNS timestamp without time zone AS

$BODY$

declare

begin

if $1 is not null then

return $1;

else

return $2;

end if;

end;

$BODY$

LANGUAGE 'plpgsql' VOLATILE

COST 100;

CREATE OR REPLACE FUNCTION nvl(timestamp with time