Hi,

I have gone through this...
If Possible change char12 to varchar12, then Ltrim and Rtrim would be able to find... This way CHAR 12 has fixed length which even the Ltrim amd Rtrim can't Trim..., This is stored as blank space.

If you know the length of column stored.. like out of 12 length it may have 5 characters long, This way use Substr to find exact values... Like
Update Table
Set Col1 = Col2
where Col1 = Substr(Col1,1,5)

This way you would be able to find...
Third option is to have both as Char 12...

Take care... Thanks