Oracle

问题 I'm trying to select the newest price from another table in a sub select. But I can't figure out how to get it working. This is what I've tried: select something, somthingelse, ( select * from ( select QUOTE_PRICE as old_price from price_history where price_history.part_no= article_table.part_no order by valid_from desc ) where rownum=1 ) from article_table where rownum < 5 The subselect works by itself, but it can't find article_table.part_no : SQL Error: ORA-00904: "article_table "."part_no

问题 I'm trying to select the newest price from another table in a sub select. But I can't figure out how to get it working. This is what I've tried: select something, somthingelse, ( select * from ( select QUOTE_PRICE as old_price from price_history where price_history.part_no= article_table.part_no order by valid_from desc ) where rownum=1 ) from article_table where rownum < 5 The subselect works by itself, but it can't find article_table.part_no : SQL Error: ORA-00904: "article_table "."part_no

问题 I've seen this sort of problems a few times and am trying to decide the best way of storing ranges in a non-overlapping manner. For example, when scheduling some sort of resource that only one person can use at a time. Mostly what I've seen is something like this: PERSON ROOM START_TIME END_TIME Col. Mustard Library 08:00 10:00 Prof. Plum Library 10:00 12:00 What's the best way of preventing new entries from overlapping an existing schedule, like say if Miss Scarlet wants to reserve the

问题 (Sorry for the long post, but I guess all the information is really necessary) We have two tables - task and subtask. Each task consists of one or more subtasks, and each of these objects has a start date, end date and duration. Additionally, subtasks have a ordering. Tables create table task ( pk number not null primary key, name varchar2(30) not null, start_date date, duration_in_days number, end_date date, needs_recomputation number default 0 ); create table subtask ( pk number not null

问题 I've seen this sort of problems a few times and am trying to decide the best way of storing ranges in a non-overlapping manner. For example, when scheduling some sort of resource that only one person can use at a time. Mostly what I've seen is something like this: PERSON ROOM START_TIME END_TIME Col. Mustard Library 08:00 10:00 Prof. Plum Library 10:00 12:00 What's the best way of preventing new entries from overlapping an existing schedule, like say if Miss Scarlet wants to reserve the

问题 I have a table column defined like this: ENTRY_STATUS NUMBER(2, 0) And in my EntityFramework class the respective field is defined like this: [Column("ENTRY_STATUS")] public int Status { get; set; } When checking the value to get an entry it works perfectly fine: var order = testDbContext.Orders.FirstOrDefault(o => o.Status > 1); But when I check the order entity after this statement it is always zero: if (order != null) { if (order.Status == 3) //Always Zero!!! { //Do something... } } What

问题 I have table that has date field. When I run a query, I see this: 01/10/2009 22:10:39 How can I retrieve only the time (IE: 22:10:39) 回答1: you can try this: SELECT TO_CHAR(yourval, 'DD-MON-YYYY HH:MI:SS') FROM yourtable; SELECT TO_CHAR(yourval, 'HH:MI:SS') FROM yourtable; Edit: as @steven pointed out, to have 24 hours style use SELECT TO_CHAR(yourval, 'HH24:MI:SS') FROM yourtable; 回答2: You need the format HH24 , since HH is only a 12 hour date. select to_char(SYSDATE, 'HH24:MI:SS') from dual

问题 What is the significance of execute immediate in PL/SQL when used with DML and DDL statements? Does execute immediate implicitly commit to a database like DDL statements do ? The following is an example I have encountered: SELECT 'TRUNCATE TABLE BD_BIDS_APPR_DET' INTO V_SQL1 FROM DUAL; EXECUTE IMMEDIATE V_SQL1; SELECT 'TRUNCATE TABLE BD_BIDS_SYS_DET' INTO V_SQL1 FROM DUAL; EXECUTE IMMEDIATE V_SQL1; SELECT 'TRUNCATE TABLE BD_BIDS_EXT_DET' INTO V_SQL1 FROM DUAL; EXECUTE IMMEDIATE V_SQL1; 回答1:

问题 I have table that has date field. When I run a query, I see this: 01/10/2009 22:10:39 How can I retrieve only the time (IE: 22:10:39) 回答1: you can try this: SELECT TO_CHAR(yourval, 'DD-MON-YYYY HH:MI:SS') FROM yourtable; SELECT TO_CHAR(yourval, 'HH:MI:SS') FROM yourtable; Edit: as @steven pointed out, to have 24 hours style use SELECT TO_CHAR(yourval, 'HH24:MI:SS') FROM yourtable; 回答2: You need the format HH24 , since HH is only a 12 hour date. select to_char(SYSDATE, 'HH24:MI:SS') from dual

问题 I have table that has date field. When I run a query, I see this: 01/10/2009 22:10:39 How can I retrieve only the time (IE: 22:10:39) 回答1: you can try this: SELECT TO_CHAR(yourval, 'DD-MON-YYYY HH:MI:SS') FROM yourtable; SELECT TO_CHAR(yourval, 'HH:MI:SS') FROM yourtable; Edit: as @steven pointed out, to have 24 hours style use SELECT TO_CHAR(yourval, 'HH24:MI:SS') FROM yourtable; 回答2: You need the format HH24 , since HH is only a 12 hour date. select to_char(SYSDATE, 'HH24:MI:SS') from dual