AS 用法: AS在mysql用来给列/表起别名. 有时,列的名称是一些表达式,使查询的输出很难理解。要给列一个描述性名称,可以使用列别名。 要给列添加别名,可以使用AS关键词后跟别名 例子1: SELECT [column_1 | expression] AS col_name
FROM table_na...
mysql errorCode 0, state 08S01 com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure ? The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. ? ? ? ? at...
mysql 模糊查询 like 语句 一 like 语句 %xxx%:查询 username 字段中包含 xxx 的记录。 select * from user where username like ‘%xxx%’; %xxx:查询 username 字段中以 xxx 结尾的记录。 select * from user where username like ‘%xxx’; xxx%:查...