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MyBatisPlus-QueryWrapper多条件查询以及修改
文章目录
MyBatisPlus-QueryWrapper多条件查询以及修改gt、ge、lt、le、isNull、isNotNulleq、nebetween、notBetweenallEqlike、notLike、likeLeft、likeRightin、notIn、inSql、notinSql、exists、notExistsor、and嵌套 or、嵌套 andorderBy、orderByDesc、orderByAsclast指定要查询的列set、setSql
gt、ge、lt、le、isNull、isNotNull
大于 >例: gt("age", 18) → age > 18ge 大于等于 >=例: ge("age", 18) → age >= 18lt 小于
QueryWrapper queryWrapper = new QueryWrapper();
queryWrapper.eq("name", "BNTang");
// selectOne:返回的是一条记录,当出现多条时会报错
User user = userMapper.selectOne(queryWrapper);
System.out.println(user);
}
between、notBetween
BETWEEN 值1 AND 值2例: between("age", 18, 30) → age between 18 and 30NOT BETWEEN 值1 AND 值2例: notBetween("age", 18, 30) → age not between 18 and 30
@Test
public void queryWrapperThree() {
QueryWrapper queryWrapper = new QueryWrapper();
queryWrapper.between("age", 20, 30);
Integer count = userMapper.selectCount(queryWrapper);
System.out.println(count);
}
allEq
allEq 全部 eq(或个别 isNull)
个别参数说明: params: key 为数据库字段名, value 为字段值 如果想表示 null isNull,则在 value 取值的时候传入一个 null, 为 null 时调用 isNull 方法, 为false时则忽略value为null的,也就是不拼接 value 为 null 的查询条件字段 例1: allEq({id:1,name:"老王",age:null})→id = 1 and name = '老王' and age is null例2: allEq({id:1,name:"老王",age:null}, false)→id = 1 and name = '老王' @Test public void queryWrapperFour() { QueryWrapper queryWrapper = new QueryWrapper(); Map queryParamsMap = new HashMap(); queryParamsMap.put("id", 1373266771933462530L); queryParamsMap.put("name", "BNTang"); queryParamsMap.put("age", 23); queryWrapper.allEq(queryParamsMap); List users = userMapper.selectList(queryWrapper); users.forEach(System.out::println); }个别参数说明 filter: 过滤函数, 是否允许字段传入比对条件中 params 与 null、IsNull 同上 例1: allEq((k,v) -> k.indexOf("a") >= 0, {id:1,name:"老王",age:null})→name = '老王' and age is null例2: allEq((k,v) -> k.indexOf("a") >= 0, {id:1,name:"老王",age:null}, false)→name = '老王'如上图可看到,只添加了一个 id 查询的条件因为我写的过滤条件为要包含 i 这个字符串,所以只有第一个 key, value 包含了所以就只添加了 id like、notLike、likeLeft、likeRight LIKE ‘%值%’例: like("name", "王")→name like '%王%'NOT LIKE ‘%值%’例: notLike("name", "王")→name not like '%王%'LIKE ‘%值’例: likeLeft("name", "王")→name like '%王'LIKE ‘值%’例: likeRight("name", "王")→name like '王%' @Test public void queryWrapperFive() { QueryWrapper queryWrapper = new QueryWrapper(); queryWrapper .notLike("name", "BNTang") .likeRight("email", "zq"); // 返回值是Map列表 List users = userMapper.selectMaps(queryWrapper); users.forEach(System.out::println); } in、notIn、inSql、notinSql、exists、notExists 字段 IN (value.get(0), value.get(1), …)例: in("age",{1,2,3})→age in (1,2,3)字段 NOT IN (value.get(0), value.get(1), …)例: notIn("age",{1,2,3})→age not in (1,2,3)字段 IN ( sql语句 )例: inSql("age", "1,2,3,4,5,6")→age in (1,2,3,4,5,6)例: inSql("id", "select id from table where id < 3")→id in (select id from table where id < 3)字段 NOT IN ( sql语句 )例: notInSql("age", "1,2,3,4,5,6")→age not in (1,2,3,4,5,6)例: notInSql("id", "select id from table where id < 3")→id not in (select id from table where id < 3)拼接 EXISTS ( sql语句 )例: exists("select id from table where age = 1")→exists (select id from table where age = 1)拼接 NOT EXISTS ( sql语句 )例: notExists("select id from table where age = 1")→not exists (select id from table where age = 1) @Test public void queryWrapperSix() { QueryWrapper queryWrapper = new QueryWrapper(); queryWrapper.in("id", 1, 2, 3); queryWrapper.inSql("id", "select id from user where id < 3"); // 返回值是Object列表 List users = userMapper.selectObjs(queryWrapper); users.forEach(System.out::println); } or、and 拼接 OR注意事项: 主动调用or表示紧接着下一个方法不是用and连接!(不调用or则默认为使用and连接) 例: eq("id",1).or().eq("name","老王")→id = 1 or name = '老王'OR 嵌套例: or(i -> i.eq("name", "李白").ne("status", "活着"))→or (name = '李白' and status '活着')AND 嵌套例: and(i -> i.eq("name", "李白").ne("status", "活着"))→and (name = '李白' and status '活着') @Test public void queryWrapperSeven() { // 修改值 User user = new User(); user.setAge(99); user.setName("BNTang6666"); // 修改条件 UpdateWrapper userUpdateWrapper = new UpdateWrapper(); userUpdateWrapper .like("name", "BNTang") .or() .between("age", 20, 30); int result = userMapper.update(user, userUpdateWrapper); System.out.println(result); }嵌套 or、嵌套 and @Test public void queryWrapperEight() { // 修改值 User user = new User(); user.setAge(99); user.setName("BNTang6666"); // 修改条件 UpdateWrapper userUpdateWrapper = new UpdateWrapper(); userUpdateWrapper .like("name", "A") .or(i -> i.eq("name", "BNTang6666").ne("age", 20)); int result = userMapper.update(user, userUpdateWrapper); System.out.println(result); } orderBy、orderByDesc、orderByAsc 排序:ORDER BY 字段, …例: orderBy(true, true, "id", "name")→order by id ASC,name ASC排序:ORDER BY 字段, … DESC例: orderByDesc("id", "name")→order by id DESC, name DESC排序:ORDER BY 字段, … ASC例: orderByAsc("id", "name")→order by id ASC,name ASC @Test public void queryWrapperNine() { QueryWrapper queryWrapper = new QueryWrapper(); queryWrapper.orderByDesc("id"); List users = userMapper.selectList(queryWrapper); users.forEach(System.out::println); } last 无视优化规则直接拼接到 sql 的最后 注意事项: 只能调用一次, 多次调用以最后一次为准有 sql 注入的风险, 请谨慎使用 例: last("limit 1") @Test public void queryWrapperTen() { QueryWrapper queryWrapper = new QueryWrapper(); queryWrapper.last("limit 1"); List users = userMapper.selectList(queryWrapper); users.forEach(System.out::println); } 指定要查询的列 @Test public void queryWrapperEleven() { QueryWrapper queryWrapper = new QueryWrapper(); queryWrapper.select("id", "name", "age"); List users = userMapper.selectList(queryWrapper); users.forEach(System.out::println); } set、setSql SQL SET 字段例: set("name", "老李头")例: set("name", "")→数据库字段值变为空字符串例: set("name", null)→据库字段值变为null设置 SET 部分 SQL例: setSql("name = '老李头'") @Test public void queryWrapperTwelve() { // 修改值 User user = new User(); user.setAge(10); // 修改条件 UpdateWrapper userUpdateWrapper = new UpdateWrapper(); userUpdateWrapper .like("name", "A") // 除了可以查询还可以使用set设置修改的字段 .set("name", "BNTang") // 可以有子查询 .setSql(" email = '[email protected]'"); int result = userMapper.update(user, userUpdateWrapper); System.out.println(result); } |
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