select problem again

hi guys,

i have another question, whats the use of this field .....kinak = ' '......in the below sample code??what does this refer to??

select kschl sakn1 kwert from konv into table con

for all entries in doc

where knumv = doc-knumv

and kinak = ' '

and kschl in ('ZU01','R100','ZC25','ZDTR','ZDTL','ZDTP','ZDDA','ZRET','ZD06','ZDMI','ZDNP','ZDNE','ZDTD',

'ZC20','ZC01','ZC02','ZC03','ZC04','ZC05','ZC06','ZC07','ZC10','ZC14','ZC18','ZM09','ZC19',

'ZC27').

thanks in advance,

gerald