pgsql -- if判斷

工具：mybatis+pgsql

詳見pgsql官方文檔

注意: 以下三種判斷查詢的結果是不一樣的

<if test = "column != null">
<if test = "column != null and column != '' ">
<if test = "column != '' ">

數據庫數據如下：

id  username   sex  address  depId  status
1     張三      男    上海     001    1
2     李四      女    上海            1
3     王五      女    上海     002    1

案例1

dao層

User select(String username，String depId); 

sql

<select id = "select"  resultType = "com.test.dto.User">
	select  username,address,sex
	  from  user
	 where status = 1
	   and  username = #{username}
   <if test = "depId != null">
       and  depId = #{depId}
   </if>
</select>

案例2

dao層

List<User> list(String address); 

sql

<select id = "list"  resultType = "com.test.dto.User">
	select  username,address,sex
	  from  user
	 where  sex = '女'  
	<if test = "address != null and address != '' ">
       and  address like '%' || #{address} || '%'
    </if>
</select>

案例3

dao層

List<User> list(String address); 

sql

<select id = "list"  resultType = "com.test.dto.User">
	select  username,address,sex
	  from  user
	 where  sex = '女'  
	<if test = "address != '' ">
       and  address like '%' || #{address} || '%'
    </if>
</select>