SQLserver LEAD和LAG函数

--测试数据
if not object_id(N'Tempdb..#T') is null
    drop table #T
Go
Create table #T([Id] varchar(10),[Value]  int )
Insert #T
select 'A',1 union all
select 'B',2 union all
select 'C',3 union all
select 'D',4 union all
select 'E',5
Go
--测试数据结束

SELECT *,
       LEAD(Value, 1, 666) OVER (ORDER BY Value) AS LEADVALUE,  --提前1行，默认值666
       LAG(Value, 2, 888) OVER (ORDER BY Value) AS LAGVALUE  --滞后2行，默认值888
FROM #T;

SELECT *,
       LEAD(Value, 1) OVER (ORDER BY Value) AS LEADVALUE,  --提前1行，默认值666
       LAG(Value, 2) OVER (ORDER BY Value) AS LAGVALUE  --滞后2行，默认值888
FROM #T;

官方文档：LAG (Transact-SQL)