Netezza / PureData – How to convert a timestamp to date in SQL

Netezza Convert Timestamp to Date
Netezza Convert Timestamp to Date

 

Since timestamps are integer, which are numbers, the date function can easily convert a timestamp to a date in Netezza SQL.

Date Function Arguments, per IBM Documentation

First argument data type Second argument data type Returns
date numeric(8,0) date

Example Timestamp to Date Conversion SQL

In this example CREATEDATE is stored as a timestamp, despite the field name.

SELECT

DATE(CREATEDDATE)

, COUNT(*) as CNT

FROM Blog.CASES_FS

GROUP BY

date(CREATEDDATE)

ORDER BY

date(CREATEDDATE);

Related References

Date/time functions

PureData System for Analytics, PureData System for Analytics 7.2.1, IBM Netezza database user documentation, Netezza SQL basics, Netezza SQL extensions, Date/time functions

Netezza date/time data type representations

PureData System for Analytics, PureData System for Analytics 7.2.0, IBM Netezza User-Defined Functions, Data type helper API reference, Temporal data type helper functions, Netezza date/time data type representations

Netezza / PureData – How to Number for day of week in SQL?

Netezza / PureData - Numeric Day of Week
Netezza / PureData – Numeric Day of Week

I had reason today to get the number of the day of the week, in PureData / Netezza, which I don’t seem to have discussed in previous posts.  So, here is a simple script to get the number for the day of week with a couple of flavors, which may prove useful.

Basic Format

select extract(dow from <<FieldName>>) from <<SchemaName>>.<<tableName>>

Example SQL

 

SELECT

CURRENT_DATE

,  TO_CHAR(CURRENT_DATE,’DAY’) AS DAY_OF_WEEK

—WEEK STARTS ON MONDAY

,  EXTRACT(DOW FROM CURRENT_DATE)-1 AS DAY_OF_WEEK_NUMBER_STARTS_ON_MONDAY

—WEEK STARTS ON SUNDAY

,  EXTRACT(DOW FROM CURRENT_DATE) AS DAY_OF_WEEK_NUMBER_STARTS_ON_SUNDAY

—WEEK STARTS ON SATURDAY

,  EXTRACT(DOW FROM CURRENT_DATE)+1 AS DAY_OF_WEEK_NUMBER_STARTS_ON_SATURDAY

FROM _V_DUAL;

 

Related References

Extract date and time values

PureData System for Analytics, PureData System for Analytics 7.2.1, IBM Netezza database user documentation, Netezza SQL basics, Functions and operators, Functions, Extract date and time values

Date/time functions

PureData System for Analytics, PureData System for Analytics 7.2.1, IBM Netezza database user documentation, Netezza SQL basics, Netezza SQL extensions, Date/time functions

Template patterns for date/time conversions

PureData System for Analytics, PureData System for Analytics 7.2.1, IBM Netezza database user documentation, Netezza SQL basics, Netezza SQL extensions, Conversion functions, Template patterns for date/time conversions

https://www.ibm.com/support/knowledgecenter/en/SSULQD_7.2.1/com.ibm.nz.dbu.doc/r_dbuser_ntz_sql_extns_templ_patterns_date_time_conv.html

Netezza / PureData – ERROR [HY000] ERROR: Bad timestamp external representation ‘0000-00-00’

SQL (Structured Query Language),  Bad timestamp external representation '0000-00-00'
Bad timestamp external representation ‘0000-00-00’

While working on a recent data conversion a data timestamp error occurred, where the legacy code and data was ‘0000-00-00’ default stamp, which was causing errors in Netezza/PureData Analytics (PDA).  ‘0000-00-00’ is not a valid timestamp in Netezza and will produce a ‘ ERROR [HY000] ERROR:  Bad timestamp external representation ‘0000-00-00’’ notice.

When handling default dates in SQL and ETL’s, generally speaking, ‘1901-01-01’ or ‘0001-01-01’ as use as defaults for null and/or invalid dates.  Both of these dates and or timestamps will insert into Netezza, which I used a quick, simple, proof table to demonstrate, which were SQL extracted and in the table below.

Valid Defaults dates in Netezza

TEST_SKTEST_TS
11901-01-01 00:00:00
2 00:00:00

Related References

Temporal data types

PureData System for Analytics, PureData System for Analytics 7.2.1, IBM Netezza database user documentation, Netezza SQL basics, Data types, Temporal data types

Netezza date/time data type representations

PureData System for Analytics, PureData System for Analytics 7.2.1, IBM Netezza user-defined functions, Data type helper API reference, Temporal data type helper functions, Netezza date/time data type representations

Date/time functions

PureData System for Analytics, PureData System for Analytics 7.2.1, IBM Netezza database user documentation, Netezza SQL basics, Netezza SQL extensions, Date/time functions