I need some help in converting or equivalent of below in postgreSQL..

From MSSQL code to postgreSQL:-

 1. CONVERT(bit,CASE WHEN column_a & 1 > 0 THEN 1 ELSE 0 END) as ABC,
 2. CONVERT(tinyint,CASE WHEN column_a IS NOT NULL THEN 0 END) as ABC
 3. CONVERT(smallint,CASE WHEN col_year = (SELECT year(col_date) 
 	FROM tab A WHERE A.a = 192) THEN 1 ELSE 0 END) as ABC,
 4. TO_CHAR(TO_CHAR(YEAR(Date))||'Y') as ABC
 5. CASE WHEN COL_A = 1 THEN TO_CHAR(YEAR(Date))||'Y' 
 6. WHEN COL_A = 4 THEN TO_CHAR (YEAR(Date) ) || 'Q' || TO_CHAR(Month(Date)/3 ) ELSE NULL END as ABC

Please help..