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SQL Language Structure

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SQL statements begin with a verb and can include clauses or names. For example:

   SELECT PartNumber FROM PurchDB.Parts

     |        |      |       |     |  |

     |        |      |     owner   |  |

     |        |      |      name   |  |

     |        |      |             |  |

   statement  |      |          table |

    verb      |      |           name |

              |      |                |

           column    +----------------+

            name              |

                              |

                            FROM

                           clause

Statements always contain a verb, one or more words that describe the action of the statement. A statement can also contain one or more clauses. A clause is a group of names and keywords describing what the verb should operate on. A verb can operate on a named object, such as a table or a column. Some statements can contain expressions or search conditions. Expressions specify a value. Search conditions screen data against specific criteria:

   SELECT * FROM PurchDB.Parts WHERE SalesPrice > 200.00

          |                    |     |             |   |

         all                   |     |      expression |

       columns                 |     |                 |

                               |     +-----------------+

                               |             |         |

                               |     search condition  |

                               |                       |

                               +-----------------------+

                                          |

                                        WHERE

                                        clause

The syntax of SQL is fully described in chapters 7-10 of this manual.

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