在特定字段中填寫的自動序列號（1,2，...）

Question

我有一個如下所示的查看錶，我想讓名爲「number」的自定義字段具有自動序列號（1,2， ...。）在列CUSTOMFIELDVALUE根據的requestId

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我需要在WOCUSTOMFIELD表的觸發器代碼，做我想做提前

感謝Lubna

Answer 1

的填寫TR igger從t獲取最大值並將其存儲在表變量中。 cte計算每個插入行的行號，並在更新階段將其添加到存儲在表變量中的值中。

use sandbox 
    go 
    --drop table t 
    --create table t(workid int identity, requestid int,customfieldvalue int) 
    --go 
    IF EXISTS (SELECT * FROM sys.triggers WHERE object_id = OBJECT_ID(N'[dbo].[tGenCustomid]')) 
    drop trigger tGenCustomid 
    go 
    CREATE TRIGGER tGenCustomid 
    ON t 
    after insert 
    AS 
    BEGIN 
     DECLARE @max TABLE (
     workid int, 
     requestid int, 
     customfieldvalue int 
    ); 

     INSERT INTO @max (requestid,customfieldvalue) 
     select requestid, 
     coalesce(max(customfieldvalue),0) 
     from  t 
     group by requestid 


     ;with cte as 
     (select i.workid,i.requestid, row_number() over (partition by i.requestid order by i.workid) rn, 
      m.customfieldvalue 
     from inserted i 
     join @max m on m.requestid = i.requestid 
    ) 
     update t 
     set customfieldvalue = cte.rn + cte.customfieldvalue 
     from t 
     join cte on cte.workid = t.workid and cte.requestid = t.requestid 

    END; 

    go 

    SET NOCOUNT ON 
    truncate table debug_table 
    truncate table t 
    print 'First bunch of inserts' 
    insert into t(requestid, customfieldvalue) 
    values 
    (1,0),(1,0), 
    (2,0),(2,0),(2,0), 
    (3,0) 

    select * from t 

    print 'Second bunch of inserts' 
    insert into t(requestid, customfieldvalue) 
    values 
    (1,0),(1,0) 
    select * from t 

    print 'Third bunch of inserts' 
    insert into t(requestid, customfieldvalue) 
    values 
    (1,0),(4,0),(3,0) 
    select * from t 

    First bunch of inserts 
    workid  requestid customfieldvalue 
    ----------- ----------- ---------------- 
    1   1   1 
    2   1   2 
    3   2   1 
    4   2   2 
    5   2   3 
    6   3   1 

    Second bunch of inserts 
    workid  requestid customfieldvalue 
    ----------- ----------- ---------------- 
    1   1   1 
    2   1   2 
    3   2   1 
    4   2   2 
    5   2   3 
    6   3   1 
    7   1   3 
    8   1   4 

    Third bunch of inserts 
    workid  requestid customfieldvalue 
    ----------- ----------- ---------------- 
    1   1   1 
    2   1   2 
    3   2   1 
    4   2   2 
    5   2   3 
    6   3   1 
    7   1   3 
    8   1   4 
    9   1   5 
    10   4   1 
    11   3   2