Преобразования типов данных (20 мин.)

Смотреть код

select
f.rental_rate,
cast(f.rental_rate as varchar(10))
from
film f;

select
1 as filed1

union all
select
1.5 as filed1;

with cte as (
select
1 as filed1
union all
select
1.5 as filed1
)

select
filed1,
pg_typeof(filed1)
from
cte;

select
cast(1 as numeric) as filed1
union all
select
1.5 as filed1;

select
1::numeric as filed1
union all
select
1.5 as filed1;

with cte as (
select
1 as filed1
union all
select
1 as filed1
)

select
filed1,

pg_typeof(filed1)
from
cte;

select
1 as filed1
union all
select
'2' as filed1;

select
1 as filed1
union all
select
'some text' as filed1;

select
cast(1 as varchar) as filed1
union all
select
'2' as filed1;

select
1 as field1
union all
select
false as field1;

select
now();

select
to_char(now(), 'yyyy---mm---dd  hh:mi');

select
to_char(now(), 'dd/mm/yyyy');

select
to_char(now(), 'dd/mon/yyyy');

select
to_char(now(), 'dd/month/yy hh24:mi:ss');

select
cast('2021-10-01' as date);

select
cast('01/10/2021 10:21' as timestamp);

select
to_date('21/10/01', 'yy/mm/dd');

select
to_timestamp('21/10/01 10:11', 'yy/mm/dd hh24:mi');