There are significant differences in the support of SQL in dBASE IV and Visual FoxPro, and some dBASE IV SQL commands are not supported in Visual FoxPro.
To work with dBASE IV data in SQL, you create a SQL database and perform operations on it in a special SQL mode. Programs using SQL must be separate and distinct from other dBASE programs (.prs v .prg programs). The semicolon is a continuation character for dBASE commands and a required command termination character for SQL commands.
Visual FoxPro supports the SQL commands ALTER TABLE, CREATE CURSOR, CREATE TABLE, DELETE, INSERT, SELECT, and UPDATE. SQL is fully integrated in Visual FoxPro. You can use SQL commands exactly as you would use any other Visual FoxPro commands, interspersing Visual FoxPro and SQL commands if you want. The semicolon is a continuation character for all Visual FoxPro and SQL commands.
Because of the significant differences between the implementation of SQL in dBASE IV and in Visual FoxPro, complex dBASE IV SQL programs may not run in Visual FoxPro and will have to be rewritten.