SQL Server allows you to use single quoted column aliases in SELECT statements:
SQL Server:
-- Using single quotes for aliases 'Current Datetime' and 'B' for two columns SELECT GETDATE() as 'Current Datetime', 'A' 'B'
In PostgreSQL you have to use double quoted aliases:
PostgreSQL:
-- Using double quotes for aliases "Current Datetime" and "B" for two columns SELECT NOW() as "Current Datetime", 'A' "B"
Both SQL Server and PostgreSQL queries return the same result:
Current Datetime | B |
2022-09-20 16:12:14.893 | A |
For more information, see SQL Server to PostgreSQL Migration.