support bool/boolean and time(n) in pg, support select..for update in…

… mysql

support extract from column, remove type keyword in mysql, support db…

….schema.column in pg

support extract function in pg

support union with last order by and limit

fix hive over partition bug

support db2

support declare in tsql

support drop procedure in tsql, fix alter column, combine drop, trunc…

…ate parsed function

support create index in transact sql

support bigquery column expr parentheses