OBIEE11g - Calculating First Day of Year, Quarter, Month in Answers

First Day of  Year: TIMESTAMPADD(SQL_TSI_DAY, -1*(DAYOFYEAR(CURRENT_DATE )-1) , CURRENT_DATE )

First Day of Quarter: TIMESTAMPADD(SQL_TSI_DAY, -1*(DAY_OF_QUARTER(CURRENT_DATE )-1) , CURRENT_DATE )

First Day of Month: TIMESTAMPADD(SQL_TSI_DAY, -1*(DAYOFMONTH(CURRENT_DATE )-1) , CURRENT_DATE )

Query For Current Year and Quarter and Month  

SELECT 
TRUNC(cast(TO_CHAR(SYSDATE,'YYYY') as VARCHAR(20))),
TRUNC(CAST(TO_CHAR(SYSDATE,'Q') AS VARCHAR(20))),
TRUNC(CAST(TO_CHAR(SYSDATE,'MM') AS VARCHAR(20)))
FROM DUAL;