IF EXISTS(SELECT 1 FROM 表 id>當前ID) SELECT TOP 1 * FROM 表 id>當前ID ORDER BY id ASC ELSE SELECT TOP 1 * FROM 表 ORDER BY id ASC
IF EXISTS(SELECT 1 FROM 表 WHERE id>當前ID) SELECT TOP 1 * FROM 表 WHERE id>當前ID ORDER BY id ASC ELSE SELECT TOP 1 * FROM 表 ORDER BY id ASC
这个是实现查询一个的代码 private void DataBind() { using (DbConnection conn = new SqlConnection("server=192.168.10.177;database=ipadress;uid=sa;pwd=111111;")) { conn.Open(); DbCommand cmd = new SqlCommand(); cmd.Connection = conn;
cmd.CommandText="select * from ipadd "; DbDataReader reader = cmd.ExecuteReader(); if (reader.Read()) { textBox1.Text = reader["fip"].ToString(); } reader.Close(); conn.Close(); } }
--定义一个变量,传入当前值(textBox1.Text) DECLARE @currentid INT SET @currentid = 2--#1.方法一 SELECT TOP 1 * FROM ( SELECT * from (SELECT TOP 1 * FROM tablename WHERE id > @currentid ORDER BY id) a UNION ALL SELECT * FROM (SELECT TOP 1 * FROM tablename ORDER BY id) b ) t ORDER BY id DESC--#2.方法二 IF EXISTS(SELECT 1 FROM tablename WHERE id > @currentid) SELECT TOP 1 * FROM tablename WHERE id > @currentid ORDER BY id ELSE SELECT TOP 1 * FROM tablename ORDER BY id
IF EXISTS(SELECT 1 FROM 表 id>當前ID)
SELECT TOP 1 * FROM 表 id>當前ID ORDER BY id ASC
ELSE
SELECT TOP 1 * FROM 表 ORDER BY id ASC
IF EXISTS(SELECT 1 FROM 表 WHERE id>當前ID)
SELECT TOP 1 * FROM 表 WHERE id>當前ID ORDER BY id ASC
ELSE
SELECT TOP 1 * FROM 表 ORDER BY id ASC
private void DataBind()
{
using (DbConnection conn = new SqlConnection("server=192.168.10.177;database=ipadress;uid=sa;pwd=111111;"))
{ conn.Open();
DbCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText="select * from ipadd ";
DbDataReader reader = cmd.ExecuteReader();
if (reader.Read())
{
textBox1.Text = reader["fip"].ToString();
}
reader.Close();
conn.Close(); }
}
DECLARE @currentid INT
SET @currentid = 2--#1.方法一
SELECT TOP 1 * FROM
(
SELECT * from (SELECT TOP 1 * FROM tablename WHERE id > @currentid ORDER BY id) a
UNION ALL
SELECT * FROM (SELECT TOP 1 * FROM tablename ORDER BY id) b
) t
ORDER BY id DESC--#2.方法二
IF EXISTS(SELECT 1 FROM tablename WHERE id > @currentid)
SELECT TOP 1 * FROM tablename WHERE id > @currentid ORDER BY id
ELSE
SELECT TOP 1 * FROM tablename ORDER BY id