1.如果需要找出u_name中既有“三”又有“猫”的记录，请使用and条件
SELECT * FROM [user] WHERE u_name LIKE ‘%三%’ AND u_name LIKE ‘%猫%’
若使用 SELECT * FROM [user] WHERE u_name LIKE ‘%三%猫%’
虽然能搜索出“三脚猫”，但不能搜索出符合条件的“张猫三”。
2.SELECT * FROM [user] WHERE u_name LIKE ‘三’
只找出“唐三藏”这样u_name为三个字且中间一个字是“三”的；
3.SELECT * FROM [user] WHERE u_name LIKE ‘[张李王]三’
将找出“张三”、“李三”、“王三”（而不是“张李王三”）；
4.SELECT * FROM [user] WHERE u_name LIKE ‘[^张李王]三’
将找出不姓“张”、“李”、“王”的“赵三”、“孙三”等；
<select id="findList" resultType="Article"> SELECT <include refid="cmsArticleColumns"/> FROM cms_article a <include refid="cmsArticleJoins"/> <where> a.del_flag = #{delFlag} <if test="title != null and title != ''"> AND a.title LIKE <if test="dbName == 'oracle'">'%'||#{title}||'%'</if> <if test="dbName == 'mssql'">'%'+#{title}+'%'</if> **<if test="dbName == 'mysql'">**CONCAT**('%', #{title}, '%')</if>** </if> <if test="posid != null and posid != ''"> AND a.posid LIKE <if test="dbName == 'oracle'">'%'||#{posid}||'%'</if> <if test="dbName == 'mssql'">'%'+#{posid}+'%'</if> <if test="dbName == 'mysql'">CONCAT('%', #{posid}, '%')</if> </if> <if test="category.id != null and category.id != ''"> AND (a.category_id = #{category.id} <if test="category.parentIds != null and category.parentIds != ''"> or c.parent_ids like <if test="dbName == 'oracle'">'%'||#{category.id}||'%'</if> <if test="dbName == 'mssql'">'%,'+#{category.id}+',%'</if> <if test="dbName == 'mysql'">CONCAT('%,', #{category.id}, ',%')</if> </if>) </if> <if test="image != null and image != ''"> AND a.image = #{image} </if> <if test="createBy != null and createBy.id != null and createBy.id != ''"> AND a.create_by = #{createBy.id} </if> <!-- ${sqlMap.dsf}--> </where> <choose> <when test="page !=null and page.orderBy != null and page.orderBy != ''"> ORDER BY ${page.orderBy} </when> <otherwise> ORDER BY a.weight DESC, a.update_date DESC </otherwise> </choose> </select>SQL— CONCAT(字符串连接函数)
MySQL: CONCAT()
Oracle: CONCAT(), ||
SQL Server: +
CONCAT() 的语法如下：
CONCAT(字串1, 字串2, 字串3, …): 将字串1、字串2、字串3，等字串连在一起。
请注意，Oracle的CONCAT()只允许两个参数；
换言之，一次只能将两个字串串连起来。不过，在Oracle中，我们可以用’||’来一次串连多个字串。
来看几个例子。假设我们有以下的表格：
Geography 表格
region_name store_name
East Boston
East New York
West Los Angeles
West San Diego
例子1:
MySQL/Oracle:
SELECT CONCAT(region_name,store_name) FROM GeographyWHERE store_name = 'Boston';
结果：
‘EastBoston’
例子2:
Oracle:
SELECT region_name || ' ' || store_name FROM GeographyWHERE store_name = 'Boston';
结果：
‘East Boston’
例子3:
SQL Server:
SELECT region_name + ' ' + store_name FROM GeographyWHERE store_name = 'Boston';
结果：
‘East Boston’