问题描述：

在Mybatis中以注解开发的方式使用动态sql拼接语句

Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '<if test='queryString != null and queryString.length > 0 '> where code = null or' at line 1
; bad SQL grammar []; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '<if test='queryString != null and queryString.length > 0 '> where code = null or' at line 1
	at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.doTranslate(SQLErrorCodeSQLExceptionTranslator.java:234)

解决方式：

在@Service注解属性中使用<script></script>包裹语句，表示以脚本方式执行

 @Select("<script>" +
                "select" +
                " * " +
                "from " +
                "t_checkitem " +
                "<if test='queryString != null and queryString.length > 0 '> " +
                "where code = #{queryString} or name = #{queryString}" +
                " </if>" +
            "</script>")
    public List<CheckItem> findPage(@Param("queryString") String queryString);