Converting YYYYDDMM to YYYY.MM.DD

Hi

after tagging my songs in mediamonkey with the proper date i refresh mp3tag an the following fields are updated:
Date and Year

My problem is, the field date is populated with DDMM

What i want is to move values in Year and Date over to RELEASETIME in the format YYYY.MM.DD
Also, my current songs have YYYYDDMM in RELEASETIME field. I just moved values in Year and Date over to RELEASETIME field. What expression can i use to convert those to YYYY.MM.DD?

thanks in advance

Use an action of the type "Replace with regular expression" for RELEASETIME
Search string: (\d\d\d\d)(\d\d)(\d\d)
Replace: $1.$2.$3

The ID3v2 frame TDRL (tag-field RELEASETIME) is a timestamp field and its format is based on a subset of ISO 8601.
Therefore the separator character "." (dot) seems not be correct.
The full date time format looks like this: "YYYY-MM-DDTHH:MM:SS".
The precision can be reduced by removing as many time indicators as needed, starting at the right edge.

DD.20150104.2152.CET

Thanks for the help
any way to turn for example: Date Year into Releasetime?
2101 2014 2014.01.21

DATE=2101
YEAR=2014
RELEASETIME=2014-01-21

Action "Format value"
Field: RELEASETIME
Formatstring: %YEAR%'-'$right(%DATE%,2)'-'$left(%DATE%,2)
... or ...
Formatstring: $regexp(%YEAR%%DATE%,'(\d\d\d\d)(\d\d)(\d\d)','$1-$3-$2')

DD.20150105.0933.CET

is it possible to select multiple fields in the Fields field?

No.
Sometimes it it possible to use the %_tag%. A list of fields is only possible if you want to delete them.

What do you want to do?

DD.20150108.2136.CET