<?xml version="1.0" encoding="UTF-8"?>

<chapter id="index"><?dbhtml dir="sql"?>

<title>SQL Statement Syntax</title>

<subtitle>Structured Query Language</subtitle>

<section id="distinct">

<title>DISTINCT</title>

<para>SELECT DISTINCT user.name FROM user</para>

<screen>

SELECT DISTINCT user.name FROM user

</screen>

</section>

<section id="groupby">

<title>group by</title>

<para>统计重复的手机号吗</para>

<screen>

select * from (select count(mobile) as c, mobile from member where length(mobile) >= 11 group by mobile) as m where m.c > 1;

</screen>

</section>

<section id="having">

<title>HAVING</title>

<programlisting>

select * from accounts where paymode='alipay' group by name having count(name) >1;

</programlisting>

</section>

<section id="regexp">

<title>REGEXP</title>

<subtitle>正则匹配</subtitle>

<para>判断非数字字符</para>

<programlisting>

select '看89700' regexp '^[0-9]+$'

select '89看700' regexp '^[0-9]+$'

select '89700看' regexp '^[0-9]+$'

</programlisting>

<para>应用到实际工作中</para>

<programlisting>

select count(*) from accounts a where a.name != '' and not a.name regexp '^[0-9]+$';

select count(*) from accounts a,members m where a.member = m.id and a.name != '' and not a.name regexp '^[0-9]+$' group by member;

SELECT * FROM tablename WHERE SUBSTRING(fieldname, 1, 1) REGEXP '[[:digit:]]';

</programlisting>

</section>

<section id="in">

<title>IN / NOT IN</title>

<programlisting>

select * from members where id in ('1','100','1000');

select * from members where group_id in (select id from members_group);

</programlisting>

</section>

<section id="any">

<title>ALL / Any</title>

<para><![CDATA[NOT IN 与 <> ALL 两个语句是相同的：]]></para>

<programlisting>

<![CDATA[

</programlisting>

<para>IN 与 "＝ANY" 两个语句是一样的：</para>

<programlisting>

SELECT s1 FROM t1 WHERE s1 = ANY (SELECT s1 FROM t2);

SELECT s1 FROM t1 WHERE s1 IN (SELECT s1 FROM t2);

</programlisting>

<example>

<title>SQL ANY example</title>

<programlisting>

<![CDATA[

</programlisting>

</example>

</section>

<section id="exists">

<title>exists, not exists</title>

<programlisting>

SELECT c.id, companyname

FROM customers c

WHERE EXISTS(

SELECT orderid FROM orders o WHERE o.customer_id = cu.id)

</programlisting>

</section>

<section id="union">

<title>UNION</title>

<para>union 分页问题</para>

<programlisting>

(SELECT a FROM tbl_name_a WHERE a=10 AND B=1)

UNION

(SELECT a FROM tbl_name_b WHERE a=11 AND B=2)

ORDER BY a LIMIT 10;

</programlisting>

<programlisting>

select * from (

select a from tbl_name_a WHERE a=10 AND B=1

union all

select a from tbl_name_b WHERE a=10 AND B=1

) tbl_name

order by a limit 0,1;

</programlisting>

<section>

<title>UNION ALL</title>

<para>UNION ALL 不会合并重复的记录</para>

<programlisting>

select a,b from tbl_name_a WHERE a=10 AND B=1

union all

select a,b from tbl_name_b WHERE a=10 AND B=1

</programlisting>

</section>

</section>

<section id="outfile">

<title>OUTFILE/LOAD DATA INFILE</title>

<para>查询结果输出到文件</para>

<screen>

SELECT * FROM tablename INTO OUTFILE '/tmp/tablename.txt';

</screen>

<para>使用tee将屏幕输出到文件</para>

<screen>

<![CDATA[

</screen>

<screen>

<![CDATA[

</screen>

<screen>

<![CDATA[

</screen>

<section id="outfile.csv">

<title>Export data to CSV from MySQL</title>

<screen>

SELECT *

INTO OUTFILE '/tmp/products.csv'

FIELDS TERMINATED BY ','

ENCLOSED BY '"'

ESCAPED BY '\\'

LINES TERMINATED BY '\n'

FROM products

</screen>

</section>

</section>

<section id="sql.mysql">

<title>MySQL 专有命令</title>

<section id="sql_no_cache">

<title>SQL_NO_CACHE</title>

<screen>

SELECT /*!40001 SQL_NO_CACHE */ * FROM table

</screen>

</section>

<section id="signal">

<title>SIGNAL Syntax</title>

<programlisting>

DROP TRIGGER `members_before_insert`;

CREATE DEFINER=`neo`@`%` TRIGGER `members_before_insert` BEFORE INSERT ON `members` FOR EACH ROW BEGIN

IF new.username IS NOT NULL THEN

IF not exists(select username from members_available where username = new.username) THEN

/*set new.username = NULL;*/

SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'An error occurred', MYSQL_ERRNO = 1001;

END IF;

END IF;

END;

</programlisting>

<screen>

</screen>

</section>

</section>

<section id="sql.92">

<title>SQL 92</title>

<para>insert + select</para>

<screen>

insert into product_type_commission select id,5,1,1,0,0,0,0,0,0 from product_type where title='notebook' and is_physical=0;

</screen>

<para>update table1,table2</para>

<screen>

begin;

ALTER TABLE `customer` ADD COLUMN `cutoff_time` TIMESTAMP NOT NULL default '0000-00-00 00:00:00';

update customer,agent set customer.cutoff_time = agent.cutoff_time where customer.id = agent.id;

ALTER TABLE `agent` DROP COLUMN `cutoff_time`;

commit;

</screen>

<para>update table1 set field1 = (select value from table2)</para>

<screen>

UPDATE

transaction

SET

transaction.total_sold_price = (

SELECT

SUM(transaction_item.price)

FROM

transaction_item

WHERE transaction_item.transaction_id = 100

)

WHERE

transaction.id = 100

</screen>

<para>update table1, (select * from other) as table2 set table1.field1 = table2.field1</para>

<screen>

UPDATE

transaction,( SELECT

SUM(product_item.bought_price) AS total_bought_price, transaction_item.transaction_id

FROM

transaction_item

WHERE

transaction_item.transaction_id IN ( '123','456' )

) as total

SET

transaction.total_bought_price = total.total_bought_price

WHERE

transaction.id = total.transaction_id

</screen>

<para>join + subquery</para>

<screen>

select u.*,t.category,t.items,t.[property] from tb_sysregchkusers as u left join (select a.items as category, b.* from (select id, items from tb_sysregchktask where categoryid=0) as a left join tb_sysregchktask as b on b.categoryid=a.id ) as t on u.taskID=t.id

select * from tb_sysregchklog where CONVERT(datetime,CONVERT(varchar(10),checkTime,120)) between convert(datetime,'2007-12-12') and convert(datetime,'2007-12-12')

</screen>

<screen>

select DISTINCT user_point_history.user_id,user.username,

(select count(id) from transaction where id = user_point_history.transaction_id) as transactions,

(SELECT SUM(u_p_h.points) FROM user_point_history as u_p_h WHERE u_p_h.type != 'RDMP' AND u_p_h.status IN('pr','ac') AND u_p_h.user_id = user_point_history.user_id) as total_points_earned,

(SELECT SUM(u_p_h.points) FROM user_point_history as u_p_h WHERE u_p_h.type = 'RDMP' AND u_p_h.status IN('pr','ac') AND u_p_h.user_id = user_point_history.user_id) as total_points_redeemed

from user_point_history,user where user_point_history.user_id = user.id;

</screen>

<para>(total_points_earned - total_points_redeemed) as current_balance_points </para>

<screen>

select user_id, username, transactions, total_points_earned, total_points_redeemed, (total_points_earned - total_points_redeemed) as current_balance_points

from (select DISTINCT user_point_history.user_id,user.username,

(select count(id) from transaction where id = user_point_history.transaction_id) as transactions,

(SELECT SUM(u_p_h.points) FROM user_point_history as u_p_h WHERE u_p_h.type != 'RDMP' AND u_p_h.status IN('pr','ac') AND u_p_h.user_id = user_point_history.user_id) as total_points_earned,

(SELECT SUM(u_p_h.points) FROM user_point_history as u_p_h WHERE u_p_h.type = 'RDMP' AND u_p_h.status IN('pr','ac') AND u_p_h.user_id = user_point_history.user_id) as total_points_redeemed

from user_point_history,user where user_point_history.user_id = user.id) as user_performance;

</screen>

<para>subquery作为一个字段使用 </para>

<screen>

select product_type_attribute.*,(select 'selected' from product_type_attribute_set where product_type_attribute_set.product_type_attribute_id = product_type_attribute.id and product_type_attribute_set.product_type_id = 26) as selected

from product_type_attribute;

</screen>

</section>

</chapter>

&chapter.sql.function.xml;