数据库中的最新条目 [英] Latest Entry in the database
问题描述
我有一个桌子名字
病人
ptn_no ipno admission_date
1 1 12/12/11
1 2 14/12/11
i想要此表中的最新条目为ptn_no 1.
帮助我进行Sql查询
如何通过入场日期匹配最新条目
如果您有主键或唯一标识列,只需按降序排序,您将获得最新记录。
要使用入场日期列获取最新记录,查询可以用几种不同的方式构建。
一种方法是使用非相关条件选择它,例如:
< pre lang =SQL> SELECT *
FROM 患者
WHERE Admission_Date =( SELECT M AX(Admission_Date) FROM 患者)
以上只有在入学日期没有重复的情况下才有效。
另一种选择可能是使用TOP,例如:
SELECT TOP ( 1 )
ptn_no,
admission_date
FROM 患者
ORDER BY admission_date DESC
如果入学日期有重复,你基本上会得到最新录取日期的随机记录。
使用录取日期的desc顺序获取记录,在类似日期的情况下ipno将通过ipno给你最新的录入
SELECT top 1 *
FROM 患者
其中 ptn_no = 1
ORDER BY admission_date , Ipno DESC
快乐编码!
:)
I have A table name
Patient
ptn_no ipno admission_date
1 1 12/12/11
1 2 14/12/11
i want the latest entry in this table for ptn_no 1.
Help me for the Sql Query
how can i match the latest entry through admission date
If you have a primary key or unique identity column, just sort by that descending and you will get the latest record right on top.
To get the latest record using the admission date column, the query can be built in several different ways.
One way is to select it using a non-correlated condition, for example:
SELECT * FROM Patient WHERE Admission_Date = (SELECT MAX(Admission_Date) FROM Patient)
The above will work only if there is no duplicates with the admission date.
Another option could be to use TOP, for example:
SELECT TOP(1) ptn_no, admission_date FROM Patient ORDER BY admission_date DESC
Again if there are duplicates for admission date, you will basically get a random record for the latest admission date.
get records using desc order of admission date and ipno in case of similar date it will give you latest entry by ipno
SELECT top 1 * FROM Patient where ptn_no = 1 ORDER BY admission_date, Ipno DESC
Happy Coding!
:)
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