GP数据库 常用SQL语句 --1,查看列名以及类型 select upper(column_name) ,data_type from information_schema.columns where table_schema='ods_hs08' and lower(table_name)=lower('T_ods_hs08_secumreal'); --2,查看表名剔除分区表名 select a.tablename from pg_tables a where a.schemaname='
select * from T_A a where a.begintime=to_date('2013-1-1','yyyy-mm-dd');和select * from T_A a where to_char(a.begintime,'yyyy-mm-dd')='2013-1-1';查询结果是一样的. 区别在于 查询的 处理步骤不一样. select * from T_A a where a.begintime=to_date('2013-1-1','yyyy-mm-dd');是先把 '201
子查询 -- 就是在一个查询中包含多个select语句(一般就2个) select id,first_name,dept_id from s_emp; 想查询和Ben一个部门的员工的id,first_name,dept_id,salary信息 select dept_id from s_emp where first_name = 'Ben'; select id,first_name,dept_id,salary from s_emp where dept_id = 上面的值; select