SQL - Syntaxe

SQL est suivi d'un ensemble unique de règles et de directives appelées Syntaxe. Ce didacticiel vous donne un démarrage rapide avec SQL en répertoriant toutes les syntaxes SQL de base.

Toutes les instructions SQL commencent par l'un des mots-clés tels que SELECT, INSERT, UPDATE, DELETE, ALTER, DROP, CREATE, USE, SHOW et toutes les instructions se terminent par un point-virgule (;).

Le point le plus important à noter ici est que SQL est insensible à la casse, ce qui signifie que SELECT et select ont la même signification dans les instructions SQL. Alors que MySQL fait la différence dans les noms de table. Donc, si vous travaillez avec MySQL, vous devez donner les noms de table tels qu'ils existent dans la base de données.

Diverses syntaxes en SQL

Tous les exemples donnés dans ce tutoriel ont été testés avec un serveur MySQL.

Instruction SQL SELECT

SELECT column1, column2....columnN
FROM   table_name;

Clause SQL DISTINCT

SELECT DISTINCT column1, column2....columnN
FROM   table_name;

Clause SQL WHERE

SELECT column1, column2....columnN
FROM   table_name
WHERE  CONDITION;

Clause SQL AND / OR

SELECT column1, column2....columnN
FROM   table_name
WHERE  CONDITION-1 {AND|OR} CONDITION-2;

Clause SQL IN

SELECT column1, column2....columnN
FROM   table_name
WHERE  column_name IN (val-1, val-2,...val-N);

Clause SQL BETWEEN

SELECT column1, column2....columnN
FROM   table_name
WHERE  column_name BETWEEN val-1 AND val-2;

Clause SQL LIKE

SELECT column1, column2....columnN
FROM   table_name
WHERE  column_name LIKE { PATTERN };

Clause SQL ORDER BY

SELECT column1, column2....columnN
FROM   table_name
WHERE  CONDITION
ORDER BY column_name {ASC|DESC};

Clause SQL GROUP BY

SELECT SUM(column_name)
FROM   table_name
WHERE  CONDITION
GROUP BY column_name;

Clause SQL COUNT

SELECT COUNT(column_name)
FROM   table_name
WHERE  CONDITION;

Clause SQL HAVING

SELECT SUM(column_name)
FROM   table_name
WHERE  CONDITION
GROUP BY column_name
HAVING (arithematic function condition);

Instruction SQL CREATE TABLE

CREATE TABLE table_name(
column1 datatype,
column2 datatype,
column3 datatype,
.....
columnN datatype,
PRIMARY KEY( one or more columns )
);

Instruction SQL DROP TABLE

DROP TABLE table_name;

Instruction SQL CREATE INDEX

CREATE UNIQUE INDEX index_name
ON table_name ( column1, column2,...columnN);

Instruction SQL DROP INDEX

ALTER TABLE table_name
DROP INDEX index_name;

Instruction SQL DESC

DESC table_name;

Instruction SQL TRUNCATE TABLE

TRUNCATE TABLE table_name;

Instruction SQL ALTER TABLE

ALTER TABLE table_name {ADD|DROP|MODIFY} column_name {data_ype};

Instruction SQL ALTER TABLE (Renommer)

ALTER TABLE table_name RENAME TO new_table_name;

Instruction SQL INSERT INTO

INSERT INTO table_name( column1, column2....columnN)
VALUES ( value1, value2....valueN);

Instruction SQL UPDATE

UPDATE table_name
SET column1 = value1, column2 = value2....columnN=valueN
[ WHERE  CONDITION ];

Instruction SQL DELETE

DELETE FROM table_name
WHERE  {CONDITION};

Instruction SQL CREATE DATABASE

CREATE DATABASE database_name;

Instruction SQL DROP DATABASE

DROP DATABASE database_name;

Instruction SQL USE

USE database_name;

Instruction SQL COMMIT

COMMIT;

Instruction SQL ROLLBACK

ROLLBACK;