数据有4W多条，不多，但是模糊查询
起来特别慢。
1，尝试过用 select * from (select * from a union all select * from b。。。很多表union) as tempTable where name like "%a%" and person_id like "%1%"，发现太慢了。。
2，尝试使用具体的字段，而不是*，即
select id,name,person_id from (select id,name,person_id from a
union all select id,name,person_id from b。。。很多表union) as tempTable where name like "%a%" and person_id like "%1%",虽然快了点儿，但是不是特别快。。
3，尝试把where放在每一个select语句中，不需要汇聚成一个表了，即少了别名：
select id,name,person_id from a where name like "%a%" and person_id like "%1%"
union all select id,name,person_id from b where name like "%a%" and person_id like "%1%"， 卧槽，出乎意料地快！解决了问题。
4，mybatis配置文件如下：
模糊查询的总数：
<select id="getFaceDataCount" resultType="int">
select sum(c) from
(<foreach collection="companyCodeList" item="item" index="index"
separator="union">select count(1) as c from ${item}
<where>
<if test="faceData.personId != null and faceData.personId != ‘‘">
and person_id like ‘%${faceData.personId}%‘
</if>
<if test="faceData.name != null and faceData.name != ‘‘">
and name like ‘%${faceData.name}%‘
</if>
</where>
</foreach>) as faceCount
</select>
模糊查询的详细：
<select id="selectAllFaceData" resultMap="BaseResultMap">
<foreach collection="companyCodeList" item="item" index="index"
separator="union">(select <include refid="Base_Column_List" /> from ${item}
<where>
<if test="faceData.personId != null and faceData.personId != ‘‘">
person_id like ‘%${faceData.personId}%‘
</if>
<if test="faceData.name != null and faceData.name != ‘‘">
and name like ‘%${faceData.name}%‘
</if>
</where>
)</foreach>
limit #{start},#{limit}
</select>
时间： 2024-10-21 03:29:32