ORA-00938: not enough arguments for function

Issue:Coalesce function is uesd in the map without placing sufficient arguments.
Ex:COALESCE(
(CASE
WHEN
 SQ_W_MCAL_PERIOD_D.ADJUSTMENT_PERIOD_FLG = 'Y' THEN
 SQ_W_MCAL_PERIOD_D.MCAL_PRIOR_PERIOD_WID
ELSE
 LKP_PERIOD_PRIOR.ROW_WID

END )
)  AS MCAL_PRIOR_PERIOD_WID

Fix:For example if we miss the replacing value in the COALESCE function then will get this error.So we need to place arguments properly.
 Ex:
 COALESCE(
(CASE
WHEN
 SQ_W_MCAL_PERIOD_D.ADJUSTMENT_PERIOD_FLG = 'Y' THEN
 SQ_W_MCAL_PERIOD_D.MCAL_PRIOR_PERIOD_WID
ELSE
 LKP_PERIOD_PRIOR.ROW_WID

END )
,0)  AS MCAL_PRIOR_PERIOD_WID