SQL基本语句总结

执行顺序:
　　SELECT select_list
　　[ INTO new_table ]
　　FROM table_source
　　[ WHERE search_condition ]
　　[ GROUP BY group_by_expression ]
　　[ HAVING search_condition ]
　　[ ORDER BY order_expression [ ASC | DESC ] ]
创建：
create database dbname；
create  table tablename (column_name1 type(size), column_name1 type(size));
束缚：
NOT NULL - 指示某列不能存储 NULL 值。
UNIQUE - 保证某列的每行必须有唯一的值。
PRIMARY KEY - NOT NULL 和 UNIQUE 的结合。确保某列（或两个列多个列的结合）有唯一标识，有助于更容易更快速地找到表中的一个特定的记录。
FOREIGN KEY - （外键）保证一个表中的数据匹配另一个表中的值的参照完整性。
CHECK - 保证列中的值符合指定的条件。
DEFAULT - 规定没有给列赋值时的默认值。

查询：
select column_name,column_name from tablename;
select * from tablename;
select distinct colunmn_name from tablename;
(where) select column_name from tablename where column_name='c1';
(like)  select column_name from tablename where column_name like 'city%';(以city结尾)
select column_name from tablename where column_name like '％city%';(包含city)
select column_name from tablename where column_name not like 'city%';(以city结尾)
(in)    select column_name from tablename where column_name in ('a','b');(column_name为a或者为b)
(between) select column_name from tablename where column_name between 10 and 20;
select column_name from tablename where column_name not between a and z;
通配符：
%   替代 0 个或多个字符
_   替代一个字符
[charlist]  字符列中的任何单一字符
[^charlist] or [!charlist]  不在字符列中的任何单一字符
（order by） select column_name from tablename where column_name='q' order by column_name ASC | DESC;
插入：(无from)
insert into tablename (column_name1,column_name2) values (v1,v2);
insert into tablename values (v1,v2,v3,);
更新：（无from）
update tablename set column_name1=c1,column_name=c2 where column_name='c';
删除：
delete from tablename where column_name='c';
top：
select top 2 * from tablename;
select top 50 percent * from tablename;
别名：
select column_name as c1,column_name as c2 from tablename as t;
连接：(inner join / left join /right join)
select column_name from tablename1 t1 inner join tablename2 t2 on t1.name=t2.name;
合并:(union）
select column_name from tablename1 union select column_name from tablename2;
请注意，UNION 内部的每个 SELECT 语句必须拥有相同数量的列。列也必须拥有相似的数据类型。同时，每个SELECT 语句中的列的顺序必须相同。
复制：
(select into) select *(或者column_name) into tablename from tablename2;
(insert into select) insert into table2 select * from table1;
索引：
create index index_name on table_name;
drop:
drop index table_name.index_name;
drop database db_name；
drop tabel table_name;
truncate table table_name;
alert:
alert table table_name add column_name type;
alert table table_name alert column column_name type;
alert table table_name drop column column_name;
函数：
AVG() - 返回平均值
COUNT() - 返回行数
FIRST() - 返回第一个记录的值
LAST() - 返回最后一个记录的值
MAX() - 返回最大值
MIN() - 返回最小值
SUM() - 返回总和

UCASE() - 将某个字段转换为大写
LCASE() - 将某个字段转换为小写
MID() - 从某个文本字段提取字符
LEN() - 返回某个文本字段的长度
ROUND() - 对某个数值字段进行指定小数位数的四舍五入
NOW() - 返回当前的系统日期和时间
FORMAT() - 格式化某个字段的显示方式

快速参考： http://www.runoob.com/sql/sql-quickref.html 
SQL 语句  语法
AND / OR    SELECT column_name(s)
FROM table_name
WHERE condition
AND|OR condition
ALTER TABLE ALTER TABLE table_name
ADD column_name datatype
or
ALTER TABLE table_name
DROP COLUMN column_name
AS (alias)  SELECT column_name AS column_alias
FROM table_name
or
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 TABLE    CREATE TABLE table_name
(
column_name1 data_type,
column_name2 data_type,
column_name2 data_type,
...
)
CREATE INDEX    CREATE INDEX index_name
ON table_name (column_name)
or
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  DELETE FROM table_name
WHERE some_column=some_value
or
DELETE FROM table_name
(Note: Deletes the entire table!!)
DELETE * FROM table_name
(Note: Deletes the entire table!!)
DROP DATABASE   DROP DATABASE database_name
DROP INDEX  DROP INDEX table_name.index_name (SQL Server)
DROP INDEX index_name ON table_name (MS Access)
DROP INDEX index_name (DB2/Oracle)
ALTER TABLE table_name
DROP INDEX index_name (MySQL)
DROP TABLE  DROP TABLE table_name
GROUP BY    SELECT column_name, aggregate_function(column_name)
FROM table_name
WHERE column_name operator value
GROUP BY column_name
HAVING  SELECT column_name, aggregate_function(column_name)
FROM table_name
WHERE column_name operator value
GROUP BY column_name
HAVING aggregate_function(column_name) operator value
IN  SELECT column_name(s)
FROM table_name
WHERE column_name
IN (value1,value2,..)
INSERT INTO INSERT INTO table_name
VALUES (value1, value2, value3,....)
or
INSERT INTO table_name
(column1, column2, column3,...)
VALUES (value1, value2, value3,....)
INNER JOIN  SELECT column_name(s)
FROM table_name1
INNER JOIN table_name2
ON table_name1.column_name=table_name2.column_name
LEFT JOIN   SELECT column_name(s)
FROM table_name1
LEFT JOIN table_name2
ON table_name1.column_name=table_name2.column_name
RIGHT JOIN  SELECT column_name(s)
FROM table_name1
RIGHT JOIN table_name2
ON table_name1.column_name=table_name2.column_name
FULL JOIN   SELECT column_name(s)
FROM table_name1
FULL JOIN table_name2
ON table_name1.column_name=table_name2.column_name
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 SELECT *
INTO new_table_name [IN externaldatabase]
FROM old_table_name
or
SELECT column_name(s)
INTO new_table_name [IN externaldatabase]
FROM old_table_name
SELECT TOP  SELECT TOP number|percent column_name(s)
FROM table_name
TRUNCATE TABLE  TRUNCATE TABLE table_name
UNION   SELECT column_name(s) FROM table_name1
UNION
SELECT column_name(s) FROM table_name2
UNION ALL   SELECT column_name(s) FROM table_name1
UNION ALL
SELECT column_name(s) FROM table_name2
UPDATE  UPDATE table_name
SET column1=value, column2=value,...
WHERE some_column=some_value
WHERE   SELECT column_name(s)
FROM table_name
WHERE column_name operator value