Postgres: integer out of range. Why this error occur?

Question

I have two queries. I expect both insert same value: 429496729600, but one of them fail because of error:

db=> update order_detail set amount = 400*1024*1024*1024 where id = 11;
ERROR:  integer out of range
db=> update order_detail set amount = 429496729600 where id = 11;
UPDATE 1

Why the error occur for first query?

UPD
Forget to specify that type of amount is bigint and the

400*1024*1024*1024 == 429496729600  

Answer 1

To force the multiplication to output a bigint instead of an int, you can cast 1 to a bigint and multiply

select cast(1 as bigint)*400*1024*1024*1024;
   ?column?
--------------
 429496729600

Answer 2

int maximum value of 2³¹-1, the first Update value greater than it so caulse the erorr.

INT -2147483648 to +2147483647

You can try to let amount column to BIGINT Type

BIGINT-9223372036854775808 to 9223372036854775807

ALTER TABLE order_detail ALTER COLUMN amount TYPE BIGINT;

Data Types

---

EDIT

we can use pg_typeof to check it out.

Query #1

postgresql will let 429496729600 be BIGINT because of the value greater than int range.

SELECT pg_typeof(429496729600 );

| pg_typeof |
| --------- |
| bigint    |

---

Query #2

When you do multiplication in number that will translate to int.

SELECT pg_typeof( 1*15*1  );

| pg_typeof |
| --------- |
| integer   |

View on DB Fiddle

Query

You can use 400*1024*1024*1024:: BIGINT let int convert to bigint.

SELECT 400*1024*1024*1024 :: BIGINT;

| ?column?     |
| ------------ |
| 429496729600 |

---

View on DB Fiddle