I am having file with data like

COLA,COLB,COLC
James,198.87,09
Jack,32.7,78
Philips,0.0,98
Jacob,0,76

I am trying to use Derived Column transformation to get value in COLB like 198.87,32.70,0.00,0.00. I have tried with different ways to convert and everytime getting error like expression error

LEN(TRIM([COLB])) == 0 ?" ": (iSNULL( (DT_DECIMAL,18,2) [COLB]) ? " " : (DT_WSTR,10) (DT_DECIMAL,18,2)[COLB])

If I remove DT_Decimal there is no expression error, How can I achieve the output using any other functions. i tried with Round function but still error.

Error at Data Flow Task [Derived Column [96]]: Cannot parse the expression "LEN(TRIM([COLB])) == 0 ?" ": (iSNULL( (DT_DECIMAL,18,2) [COLB]) ? " " : (DT_WSTR,10) (DT_DECIMAL,18,2)[COLB])". The expression was not valid, or there is an out-of-memory error.