Commented by: Bert Herngreen (bertherngreen)

CORE1341, 'Date format when casting as varchar', is closed and marked as a duplicate of this CORE1314.

Therefore I ask my question here: What about a (non-sql-standard) extension of CAST e.g.:

CAST (START_DATE AS CHAR(8) FORMAT 'yyyymmdd')
or even:
CAST ('18-08-2010' FORMAT 'dd-mm-yyyy' AS CHAR(8) FORMAT 'yyyymmdd')

Bert

Commented by: @WarmBooter

A format function would be nice, like described in CORE1341. I dont think this issue is the same as described in 1341. A function to be able to format dates and numbers (money, etc) would be nice addition to the internal function list.

Commented by: @mrotteveel

The syntax suggested by Bert Herngreen is almost the same as defined in the standard (SQL:2016-2 6.13 <cast specification>):

"""
<cast specification> ::=
CAST <left paren>
<cast operand> AS <cast target>
[ FORMAT <cast template> ]
<right paren>

<cast operand> ::=
<value expression>
| <implicitly typed value specification>

<cast target> ::=
<domain name>
| <data type>

<cast template> ::=
<character string literal>
"""

Where <cast template> follows the rules of Subclause 9.42, "Converting a datetime to a formatted character string" or Subclause 9.43, "Converting a formatted character string to a datetime".