I want to write some queries which can work in almost all the databases without any SQLExceptions. So, where can I get the ANSI standards to write the queries ?
Not sure that'll help you.
Vendors are touch and go as far as standards implementation and often the standards themselves are imprecise enough such that you could never write a query that would work with all implementors.
For example, SQL 92 defines the concatenation operator as || but neither MySQL nor MSSQL use this (Oracle does). Vendor independent string concatenation is impossible.
Similarly, a standard escape character is not specified so how you handled that might not work in all vendors.
Having said that:
SQL 92: http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt
Wiki article with links to SQL 99 ISO documents: http://en.wikipedia.org/wiki/SQL:1999