create view reader_message as select reader_name ,name,id_num , DATEDIFF( year, CONVERT ( DATE, SUBSTRING(id_num, 7, 4) + '-' + SUBSTRING(id_num , 11, 2) + '-' + SUBSTRING(id_num, 13, 2) ) , GETDATE() ) ) as age, phone_num from readers;请问这一段的代码的错误是什么

这段代码存在一个多余的右括号，导致 SQL 语法错误。正确的代码如下所示：

create view reader_message as
select reader_name, name, id_num,
       DATEDIFF( year, CONVERT( DATE, SUBSTRING(id_num, 7, 4) + '-' + SUBSTRING(id_num, 11, 2) + '-' + SUBSTRING(id_num, 13, 2)), GETDATE()) as age,
       phone_num
from readers;

注意：这里假设你已经创建了一个名为 `readers` 的表，该表包含有关读者的信息，如姓名、身份证号、电话号码等。

相关问题

create trigger tri_jieshu on reader_borrow for insert as declare @id varchar(50) select @id=borrow_id from inserted update book_borrowing set book_surplus=book_surplus-1 where book_id=@id create trigger tri_huanshu on reader_back for insert as declare @id varchar(50) select @id=back_id from inserted update book_borrowing set book_surplus=book_surplus+1 where book_id=@id create proc payment @id varchar(20),@name varchar(20) as begin select borrow_date,back_date from reader_back,reader_borrow where back_id=borrow_id and back_id=@id and borrow_bookname=back_bookname and (select datediff(day, borrow_date,back_date) FROM reader_back,reader_borrow)>7 end create view view_pay as select * from reader_back,reader_borrow where (borrow_id=back_id and borrow_bookname=back_bookname) create proc proc_pay (@id varchar(20)) as select back_id,back_bookname,back_date,borrow_date from view_pay where back_id=@id exec proc_pay @id='1'该代码有什么语法错误

在触发器 tri_jieshu 和 tri_huanshu 中，update 语句中的 where 子句需要指定 book_id 而不是 borrow_id 和 back_id。应该修改为：

update book_borrowing set book_surplus=book_surplus-1 where book_id=(select book_id from inserted)

和

update book_borrowing set book_surplus=book_surplus+1 where book_id=(select book_id from inserted)

在 payment 存储过程中，应该将 datediff 函数的返回值赋值给一个变量，然后使用该变量进行比较。应该修改为：

create proc payment @id varchar(20),@name varchar(20) as     
begin         
    declare @days int
    select @days = datediff(day, borrow_date,back_date) FROM  reader_back,reader_borrow
    where back_id=borrow_id and back_id=@id and borrow_bookname=back_bookname 
    if (@days > 7)
    begin
        select borrow_date,back_date from reader_back,reader_borrow
        where back_id=borrow_id and back_id=@id and borrow_bookname=back_bookname
    end
end

在 proc_pay 存储过程中，应该将 @id 的数据类型修改为 varchar(50)，并且在查询结果中使用别名来避免列名冲突。应该修改为：

create proc proc_pay (@id varchar(50)) as  
begin
    select b.back_id, b.back_bookname, b.back_date, r.borrow_date
    from reader_back b, reader_borrow r
    where b.back_id = r.borrow_id and b.back_id = @id and b.borrow_bookname = r.back_bookname
end

exec proc_pay @id='1'

select * from ( SELECT P.PATIENT_ID, P.VISIT_ID, PM.NAME, PM.SEX, P.ADMISSION_DATE_TIME, ( SELECT TOP 1 DP.DEPT_NAME FROM DEPT_DICT DP WHERE DP.DEPT_CODE = P.DEPT_ADMISSION_TO ) AS DEPT_ADM, P.DISCHARGE_DATE_TIME, ( SELECT TOP 1 DP.DEPT_NAME FROM DEPT_DICT DP WHERE DP.DEPT_CODE = P.DEPT_DISCHARGE_FROM ) AS DEPT_DIS, DATEDIFF( DAY, P.ADMISSION_DATE_TIME, P.DISCHARGE_DATE_TIME ) AS INPAT_DAYS, P.DOCTOR_IN_CHARGE --datediff(day, P.ADMISSION_DATE_TIME,P.DISCHARGE_DATE_TIME) as zyts FROM PAT_VISIT P INNER JOIN PAT_MASTER_INDEX PM ON PM.PATIENT_ID = P.PATIENT_ID WHERE select * from ( SELECT P.PATIENT_ID, P.VISIT_ID, PM.NAME, PM.SEX, P.ADMISSION_DATE_TIME, ( SELECT TOP 1 DP.DEPT_NAME FROM DEPT_DICT DP WHERE DP.DEPT_CODE = P.DEPT_ADMISSION_TO ) AS DEPT_ADM, P.DISCHARGE_DATE_TIME, ( SELECT TOP 1 DP.DEPT_NAME FROM DEPT_DICT DP WHERE DP.DEPT_CODE = P.DEPT_DISCHARGE_FROM ) AS DEPT_DIS, DATEDIFF( DAY, P.ADMISSION_DATE_TIME, P.DISCHARGE_DATE_TIME ) AS INPAT_DAYS, P.DOCTOR_IN_CHARGE --datediff(day, P.ADMISSION_DATE_TIME,P.DISCHARGE_DATE_TIME) as zyts FROM PAT_VISIT P INNER JOIN PAT_MASTER_INDEX PM ON PM.PATIENT_ID = P.PATIENT_ID WHERE P.DISCHARGE_DATE_TIME >= '2016-01-01' AND P.DISCHARGE_DATE_TIME < = '2023-07-10' AND DATEDIFF( DAY,P.ADMISSION_DATE_TIME, P.DISCHARGE_DATE_TIME ) >= 30 ) t order by inpat_days desc P.DISCHARGE_DATE_TIME >= '2016-01-01' AND P.DISCHARGE_DATE_TIME < = '2023-07-10' AND DATEDIFF( DAY,P.ADMISSION_DATE_TIME, P.DISCHARGE_DATE_TIME ) >= 30 ) t order by inpat_days desc 帮我把这段sql优化一下

这段 SQL 查询语句可以进行一些优化，例如使用表别名、避免多次嵌套子查询等。下面是优化后的 SQL 查询语句：

SELECT
    P.PATIENT_ID,
    P.VISIT_ID,
    PM.NAME,
    PM.SEX,
    P.ADMISSION_DATE_TIME,
    DP_ADM.DEPT_NAME AS DEPT_ADM,
    P.DISCHARGE_DATE_TIME,
    DP_DIS.DEPT_NAME AS DEPT_DIS,
    DATEDIFF(DAY, P.ADMISSION_DATE_TIME, P.DISCHARGE_DATE_TIME) AS INPAT_DAYS,
    P.DOCTOR_IN_CHARGE 
FROM
    PAT_VISIT P
    INNER JOIN PAT_MASTER_INDEX PM ON PM.PATIENT_ID = P.PATIENT_ID 
    LEFT JOIN DEPT_DICT DP_ADM ON DP_ADM.DEPT_CODE = P.DEPT_ADMISSION_TO
    LEFT JOIN DEPT_DICT DP_DIS ON DP_DIS.DEPT_CODE = P.DEPT_DISCHARGE_FROM
WHERE
    P.DISCHARGE_DATE_TIME >= '2016-01-01'
    AND P.DISCHARGE_DATE_TIME <= '2023-07-10'
    AND DATEDIFF(DAY, P.ADMISSION_DATE_TIME, P.DISCHARGE_DATE_TIME) >= 30
ORDER BY
    INPAT_DAYS DESC;

此优化后的查询使用了表别名，将子查询转换为了左连接，并通过 JOIN 操作将 DEPT_DICT 表连接到主查询中，以减少子查询的数量。同时，将过滤条件放在 WHERE 子句中，使用了统一的日期格式。

请注意，优化 SQL 语句时需要考虑数据库的具体情况和索引的使用，这只是一个基本的优化示例，具体优化策略可能需要根据实际情况进行调整。