工作总结

sql：

left  join  on  where

错误：

select count(c.*) from c  left join b on c.id=b.id where b.title='test';  

正确：

select count(*) from c  left join b on c.id=b.id where b.title='test';  

关于导出数据到文件中：首先mysql用户需要拥有file权限  into  outfile 

select * from  table  limit a,b into outfile "e:/test.txt"';

或者

select * into outfile "e:/test.txt" from table 

SELECT * INTO OUTFILE "e:/test.txt"   FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '\"' FROM wlapp_book

权限问题：

在root权限下面给wlapp账户分配数据库ltadmin的管理权限
GRANT SELECT, INSERT, UPDATE, DELETE ON ltadmin.* TO wlapp@'127.0.0.1'
GRANT SELECT, INSERT, UPDATE, DELETE ON ltadmin.* TO wlapp@'admin'




主要是mysql数据库中的db表和user表