insert into second table, where a null rows exist

Hi all!

I got a Problem and dont know, how should I solve this case

so...

there are 2 tables PS_DOC and WD_KDOC_NEU.

Table WD_KDOC_NEU got 25056875 rows, but there are also 325209 NULL rows in column KD_LNR_DEST_PS_DOC.

I would like to insert all rows into WD_KDOC_NEU table from PS_DOC table, where the rows are null.

Basically, I have to add the following data and fill my WD_KDOC_NEU table.

Source	Destination
PS_DOC.KD_LNR_DEST	WD_KDOC_NEU.KD_LNR_DEST_PS_DOC

described tables:

desc WD_KDOC_NEU