[大数据]MySql实现动态拼接查询

数据准备：

-- 简单创建一个表
CREATE TABLE `subject` (
  `ID` int NOT NULL,
  `CLASSID` int DEFAULT NULL,
  `SUBJECTNAME` varchar(20) DEFAULT NULL,
  `score` float(5,2) DEFAULT NULL,
  `GARDEID` int DEFAULT NULL
)

-- 插入俩组数据
INSERT INTO subject
(ID, CLASSID, SUBJECTNAME, score, GARDEID)
VALUES(1, 8, 'java', 81.9, 56);
INSERT INTO subject
(ID, CLASSID, SUBJECTNAME, score, GARDEID)
VALUES(2, 11, 'java', 117.24, 49);

sql实现动态查询

set @select  = ' select * from ';
set @table  = 'subject s';
set @where = ' limit 2';
set @sqls = concat(@select, @table,@where);
PREPARE stmt FROM @sqls;
EXECUTE stmt ;