How to write SQL queries compatible with most databases

What are ODBC Escape Sequences?

ODBC Escape sequences have included in ODBC standard and allows write SQL queries which compatible with many DBMS. Firebird and Interbase does not contains own implementation for escape sequences and therefore we have implemented them in IBProvider and now users can write compatible SQL queries for Firebird and Interbase as for MS SQL Server, Oracle, My SQL, PostgreSQL, DB2 and etc.

At first time ODBC sequences was implemented for ODBC drivers, but bit by bit they was implemented in OLE DB drivers such as Microsoft Ole Db Provider for SQL Server, IBProvider and others.

Why use ODBC Escape sequences?

Some SQL capabilities like calling of scalar functions or stored procedures in different DBMS implemented by different ways. But ODBC Escape Sequences define unified syntax for these operations and provide compatible and standard notation.

For the first example let's take string concatenation case. In Firebird and Oracle string concatenation has used ‘||' operator, but in MS SQL Server string concatenation has made by ‘+' operator. We must write SQL query which will be compatible with most DBMS.

Let write best SQL concatenation