SQL语言快速参考

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SQL语言快速参考
SQL是用于访问和处理数据库的标准的计算机语言,这些数据库系统包括 MS SQL Server、Oracle、MySQL  等。
通过 SQL 创建数据库、表、索引,及其删除它们。
通过SQL 可以在数据库中执行查询、获取数据、插入新的记录、删除记录以及更新记录。

下表来源 https://www.w3school.com.cn/sql/sql_quickref.asp

语句

语法

AND / OR

SELECT column_name(s)
FROM table_name
WHERE condition
AND|OR condition

ALTER TABLE (add column)

ALTER TABLE table_name
ADD column_name datatype

ALTER TABLE (drop column)

ALTER TABLE table_name
DROP COLUMN column_name

AS (alias for column)

SELECT column_name AS column_alias
FROM table_name

AS (alias for table)

SELECT column_name
FROM table_name  AS table_alias

BETWEEN

SELECT column_name(s)
FROM table_name
WHERE column_name
BETWEEN value1 AND value2

CREATE DATABASE

CREATE DATABASE database_name

CREATE INDEX

CREATE INDEX index_name
ON table_name (column_name)

CREATE TABLE

CREATE TABLE table_name
(
column_name1 data_type,
column_name2 data_type,
.......
)

CREATE UNIQUE INDEX

CREATE UNIQUE INDEX index_name
ON table_name (column_name)

CREATE VIEW

CREATE VIEW view_name AS
SELECT column_name(s)
FROM table_name
WHERE condition

DELETE FROM

DELETE FROM table_name
(Note: Deletes the entire table!!)

or

DELETE FROM table_name
WHERE condition

DROP DATABASE

DROP DATABASE database_name

DROP INDEX

DROP INDEX table_name.index_name

DROP TABLE

DROP TABLE table_name

GROUP BY

SELECT column_name1,SUM(column_name2)
FROM table_name
GROUP BY column_name1

HAVING

SELECT column_name1,SUM(column_name2)
FROM table_name
GROUP BY column_name1
HAVING SUM(column_name2) condition value

IN

SELECT column_name(s)
FROM table_name
WHERE column_name
IN (value1,value2,..)

INSERT INTO

INSERT INTO table_name
VALUES (value1, value2,....)

or

INSERT INTO table_name
(column_name1, column_name2,...)
VALUES (value1, value2,....)

LIKE

SELECT column_name(s)
FROM table_name
WHERE column_name
LIKE pattern

ORDER BY

SELECT column_name(s)
FROM table_name
ORDER BY column_name [ASC|DESC]

SELECT

SELECT column_name(s)
FROM table_name

SELECT *

SELECT *
FROM table_name

SELECT DISTINCT

SELECT DISTINCT column_name(s)
FROM table_name

SELECT INTO
(used to create backup copies of tables)

SELECT *
INTO new_table_name
FROM original_table_name

or

SELECT column_name(s)
INTO new_table_name
FROM original_table_name

TRUNCATE TABLE
(deletes only the data inside the table)

TRUNCATE TABLE table_name

UPDATE

UPDATE table_name
SET column_name=new_value
[, column_name=new_value]
WHERE column_name=some_value

WHERE

SELECT column_name(s)
FROM table_name
WHERE condition

MySQL、Oracle、SQL Server大小写情况

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