Redis cluster 擴容與縮容
阿新 • • 發佈:2022-12-02
-- 子查詢 -- 先根據"湯姆"查詢出對應的部門編號! select dept_id from tb_emp where emp_name = '湯姆'; -- 在部門資訊表,根據部門編號查詢部門名稱! select dept_name from tb_dept where dept_id = 101; -- 組合 select dept_name from tb_dept where dept_id = ( select dept_id from tb_emp where emp_name = '湯姆' ); -- 查詢“cat”在10月份工資情況! -- 先根據"cat"查詢對應的員工編號select emp_id from tb_emp where emp_name = 'cat'; -- 根據員工編號2查詢工資情況 select * from tb_salary where s_put_time = '2022-10-10' and emp_id = 2; -- 組合 select * from tb_salary where s_put_time = '2022-10-10' and emp_id = ( select emp_id from tb_emp where emp_name = 'cat' ); -- 查詢“湯姆”和“cat”相同部門的員工資訊! -- 根據“湯姆”和“cat”查詢對應的部門編號select dept_id from tb_emp where emp_name = '湯姆' or emp_name ='cat'; -- 根據部門編號查詢員工資訊 select * from tb_emp where dept_id = 101; -- 當子查詢返回是多個結果集! 使用in select * from tb_emp where dept_id in ( select dept_id from tb_emp where emp_name = '湯姆' or emp_name ='cat' );
-- 子查詢當做臨時表來使用! select * from tb_emp e, tb_salary s wheree.emp_id = s.s_id order by dept_id; select * from ( select e.*,s.s_put_time,s.s_salary,s.s_state from tb_emp e, tb_salary s where e.emp_id = s.s_id )tab where tab.s_put_time > '2022-10-01'; -- 檢視每個部門最高工資的員工資訊 -- 根據部門來分組,獲取最高工資 select e.dept_id,max(s.s_salary) from tb_emp e, tb_salary s where e.emp_id = s.emp_id group by e.dept_id; -- 根據部門編號和工資查詢員工資訊 select e.* from tb_emp e, tb_salary s where e.emp_id = s.emp_id and e.dept_id = 101 and s.s_salary = 60000; -- 合併 select e.* from tb_emp e, tb_salary s,( select e.dept_id,max(s.s_salary) maxsal from tb_emp e, tb_salary s where e.emp_id = s.emp_id group by e.dept_id )tab where e.emp_id = s.emp_id and e.dept_id = tab.dept_id and s.s_salary = tab.maxsal; -- 檢視每個部門最高工資的員工資訊 --> any select e.* from tb_emp e, tb_salary s where e.emp_id = s.emp_id and (e.dept_id,s.s_salary) = any ( select e.dept_id,max(s.s_salary) from tb_emp e, tb_salary s where e.emp_id = s.emp_id group by e.dept_id );
-- 臨時列使用 select e.*,( select dept_name from tb_dept where dept_id = e.dept_id) deptName from tb_emp e;