Extracting Day of Week as an Integer with Netezza SQL

Question

This should be doable, but how can I extract the day of the week from a field containing data in date format with Netezza SQL? I can write the following query:

SELECT date_part('day',a.report_dt) as report_dt FROM table as a

but that gives me the day of the month.

thanks for any help

Answer 1

The below queries give day numbers for any week,month,year for a particular date.

--Day of Week 
SELECT EXTRACT(dow FROM report_dt) FROM table;
--Day of Month
SELECT DATE_PART('day', report_dt) FROM table;
--Day of Year
SELECT EXTRACT(doy FROM report_dt) FROM table;

Answer 2

Netezza is just ANSI SQL, originally derived from PostgreSQL. I'd expect this to work.

select extract(dow from a.report_dt) as report_dt
from table as a

Returns values should range from 0 to 6; 0 is Sunday. You might expect that to be an integer, but in PostgreSQL at least, the returned value is a double-precision floating point.

Answer 3

如果要直接提取日期名称：

Select to_char(date, 'Day') as Day_Name From table;

Answer 4

在 Netezza SQL 中，SELECT EXTRACT(dow FROM report_dt) 将返回值 1 到 7。1 是星期日，7 是星期六。