, , . , , . , SQL ( ), .
SQL . , . SQL - . , , , , . SQL , . SQL , . , - , , , .
. - , , - , , , ( - "" ""). SQL , , " " " ".
SQL-, : DDL,. DML DCD.
()
SQL, , DDL (Data Definition Language).
.
CREATE TABLE .
CREATE TABLE (_ integer, _ text (20), text (50), _ date, primary KEY (_))
| _ | _ | _ | |
_, :
- _ ;
- _ - 20 ;
- _ - 50 ;
- _ .
. , .. , .
DROP TABLE .
DROP TABLE ;
, .
().
DML (Data Manipulation Language). DML , , .
|
|
|
:
1. SELECT , , .
:
SELECT 1, 2, , N
FROM
WHERE
SELECT , _
FROM
WHERE []= and [_] > 1963
| _ | _ | ||
| The Beatles | |||
| Led Zeppelin | |||
| U2 |
:
| _ | |
| Led Zeppelin |
2. INSERT , , , . .
:
INSERT
INTO ( 1, 2, , N)
VALUES ( 1, 2,, N)
INSERT N .
INSERT
INTO (_, _, )
VALUES (5, "The_Beatles", "")
(_, _, ) .
3. DELETE , .
:
DELETE 1, 2, , N
FROM
WHERE
, DELETE, *.
, _ >= 5
DELETE *
FROM
WHERE [_]>=5
( Access)
:
DELETE * FROM
4. UPDATE () , .
:
UPDATE
SET 1= 1,, N = N
WHERE
_ - Led Zeppelin 5
UPDATE
SET [_] = " Led Zeppelin "
WHERE [_] =5
SQL, , DDL (Data Definition Language).
