<if test="bj != null and bj != ''"> HAVING COUNT(*) >= 5 </if>这样写对吗
时间: 2024-04-01 15:34:42 浏览: 10
是的,这个if语句的写法是正确的。这个if语句的作用是当`bj`参数不为`null`并且不为空字符串时,将`HAVING COUNT(*) >= 5`这个条件添加到SQL语句中。
这个if语句的意思是,如果传入`bj`参数,且该参数不为`null`并且不为空字符串(即有值),则在查询结果中对数据进行分组,并筛选出分组后数量大于等于5的数据。如果`bj`参数为`null`或者为空字符串,则不会添加该条件到SQL语句中,查询结果中不会进行分组。
需要注意的是,这个if语句只是一个条件判断,它需要嵌套在其他SQL语句中使用,例如在select语句的后面,或者在where语句的后面。
相关问题
<select id="selectSysRpuserListByToday" parameterType="SysRpuser" resultMap="SysRpuserResult"> <include refid="selectSysRpuserVo"/> <where> <if test="tid != null and tid != ''"> and tid = #{tid}</if> <if test="tusername != null and tusername != ''"> and tusername like concat('%', #{tusername}, '%')</if> <if test="tnickname != null and tnickname != ''"> and tnickname like concat('%', #{tnickname}, '%')</if> <if test="uamount != null and uamount != ''"> and uamount = #{uamount}</if> <if test="ustatus != null and ustatus != ''"> and ustatus = #{ustatus}</if> <if test="forgroup != null and forgroup != ''"> and forgroup = #{forgroup}</if> <if test="createtime != null "> and createtime = #{createtime}</if> <if test="agentTid != null and agentTid != ''"> and agentTid = #{agentTid}</if> </where> </select>优化以上代码,要求能查询当日数据
可以在 `<where>` 标签中添加对 `createtime` 字段的判断,使查询仅返回当日的数据。具体代码如下:
```xml
<select id="selectSysRpuserListByToday" parameterType="SysRpuser" resultMap="SysRpuserResult">
<include refid="selectSysRpuserVo"/>
<where>
<if test="tid != null and tid != ''"> and tid = #{tid}</if>
<if test="tusername != null and tusername != ''"> and tusername like concat('%', #{tusername}, '%')</if>
<if test="tnickname != null and tnickname != ''"> and tnickname like concat('%', #{tnickname}, '%')</if>
<if test="uamount != null and uamount != ''"> and uamount = #{uamount}</if>
<if test="ustatus != null and ustatus != ''"> and ustatus = #{ustatus}</if>
<if test="forgroup != null and forgroup != ''"> and forgroup = #{forgroup}</if>
<!-- 添加当日数据判断 -->
<if test="createtime != null">
and createtime >= #{createtime}
and createtime <= DATE_ADD(#{createtime}, INTERVAL 1 DAY)
</if>
<if test="agentTid != null and agentTid != ''"> and agentTid = #{agentTid}</if>
</where>
</select>
```
这个代码中,`DATE_ADD(#{createtime}, INTERVAL 1 DAY)` 表示将 `#{createtime}` 的日期加 1 天,相当于查询当日的数据。
在Java代码中,可以这样调用:
```java
SysRpuser obj = new SysRpuser();
obj.setCreatetime(new Date());
List<SysRpuserResult> result = sqlSession.selectList("selectSysRpuserListByToday", obj);
```
这样,就可以查询出当日的数据了。
SELECT u.*, g.group_name, l.name as level_name FROM eb_user u LEFT JOIN eb_user_group g ON u.group_id = g.id LEFT JOIN eb_system_user_level l ON u.`level` = l.id <where> <if test="nickname!=null and nickname!=''"> u.real_name CONCAT('%',nickname,'%') or u.phone = nickname </if> <if test="loginType!=null and loginType!=''"> and u.user_type = loginType </if> <if test="level!=null"> and u.level = level </if> <if test="groupId!=null and groupId!=''"> and u.group_id = groupId </if> <if test="tagId!=null"> and u.tag_id in(tagId) </if> <if test="cardId!=null and cardId!=''"> and u.is_promoter = cardId </if> <if test="country!=null and country!=''"> and u.country = country </if> <if test="sex!=4"> and u.sex = sex </if> </where>你把它优化一下,同时把优化后的代码给我
好的,我将对您提供的查询进行优化,并提供优化后的代码:
```sql
SELECT
u.*,
g.group_name,
l.name AS level_name
FROM
eb_user u
LEFT JOIN eb_user_group g ON u.group_id = g.id
LEFT JOIN eb_system_user_level l ON u.`level` = l.id
WHERE
1 = 1
<if test="nickname!=null and nickname!=''">
AND (u.real_name LIKE CONCAT('%', #{nickname}, '%') OR u.phone = #{nickname})
</if>
<if test="loginType!=null and loginType!=''">
AND u.user_type = #{loginType}
</if>
<if test="level!=null">
AND u.level = #{level}
</if>
<if test="groupId!=null and groupId!=''">
AND u.group_id = #{groupId}
</if>
<if test="tagId!=null">
AND u.tag_id IN
<foreach item="item" collection="tagId" open="(" close=")" separator=",">
#{item}
</foreach>
</if>
<if test="cardId!=null and cardId!=''">
AND u.is_promoter = #{cardId}
</if>
<if test="country!=null and country!=''">
***