This is an attempt to introduce you to SQL and to explain what relational databases are, what the relational data model is and how you can extract data from databases with SQL.
The author has written this SQL-help in his free time because a quick and permanently online SQL-tutorial was needed. This is only a part of the whole SQL-standart, for more information about its implementations on different database systems please contact the software manyfacturers. The "Standard-SQL", first developed by IBM, was improved by software firms that develop relational database management systems (RDBMS). But all of this improvements can not be discussed in an brief help file. The small table after the command/keyword indicates in some cases, in wich system this command/keyword is implemented.
The author has written this SQL-help in his free time because a quick and permanently online SQL-tutorial was needed. This is only a part of the whole SQL-standart, for more information about its implementations on different database systems please contact the software manyfacturers. The "Standard-SQL", first developed by IBM, was improved by software firms that develop relational database management systems (RDBMS). But all of this improvements can not be discussed in an brief help file. The small table after the command/keyword indicates in some cases, in wich system this command/keyword is implemented.
