The SQl statements are used to fetch/retrieve, update, insert, delete data from the database. In PeopleSoft we use the sql stmts using sqlexec or createsql.Differnet sql statements are:Select, Insert, Update, Delete.
Metasql statement->
Differnet RDBMS have differne date and time formats. though the component processor takes care of the automatic convesion but at the time of using the sqlexec the automatic conversion does not take place. So in order to understand this the meta sql concept has come. Whcih we can use in diff sql stmts. for example %datetimein, %date, %time, %currentdatetime,  %datetimeout etc.
%dateIn: This is used in the where caluse of "Select and update"
%dateout: This is used while selecting the data.