Structured Query Language

Structured Query Language

1. Syntax.

   • Keyword are Not case sensitive.
   • * = All.
   • After each command a ';' is needed to show the end.
     • This is not needed after each line.
   • % = missing words.

2. Select.

   • Allows data to be selected from a Database.
     • More than one selection can be made, all separated with a comma.
   • Needs From statement to specify which database to select from.

3. Distinct.

   • Removes all of the Duplicates from a Selection.

4. Where.

   • Allows Data to be Filtered. ie: only select records where country = 'Germany'.

5. And/Or.

   • And Allows Records to be selected based on two values. ie: where sex = male AND age = < 30.
   • Or allows data to be selected based on either of two values. ie: Sex = male OR Age = < 30.

6. Order By.

   • Allows a Database or selection to be ordered by a specific thing. ie: CustomerNames in descending order.

7. Insert Into.

   • Allows Data to be added to a database.

8. Update.

   • Allows date to be modified in a database.
   • Where statement needed to make sure all records are not modifies.

9. Delete.

   • Allows records to be deleted from a database.
   • Needs Where statement to make sure not all records are deleted.

10. From.

    • Tells it what to do the operation on.

11. Like.

    • Allows a pattern to be searched for.

12. Drop.

    • Allows an entire database to be deleted.

13. Join.

    • Allows all data from two data bases to be joined together, if the columns match.

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