C#中肿么读取SQL数据库表中的数据后显示在一个TEXTBOX中?

private void GetDataByParmSqlCommand()
{
SqlConnection sqlc = new SqlConnection(DBUtility.SqlHelper.ConnectionStringLocalTransaction); //取连接字符串饼建立sqlconnection
try
{

sqlc.Open();
SqlCommand com = new SqlCommand(select * from c6 where usr_id = usr_id, sqlc);
SqlParameter parm = new SqlParameter();
parm.ParameterName = @usr_id;
parm.Value = 01;
com.Parameters.Add(parm);
com.ExecuteNonQuery();
DataSet ds = new DataSet();
SqlDataAdapter sda = new SqlDataAdapter(com);
sda.Fill(ds, c6);
DataTable dt = ds.Tables[0];
textbox.Text =用户代码：+ dt.Rows[0][usr_id].ToString().Trim() +用户名称：+ dt.Rows[0][usr_name].ToString().Trim() ;
//这样组合一下就可以了,看你要显示哪些信息

}
catch (Exception ee)
{
MessageBox.Show(ee.Message, );
}
finally
{
sqlc.Close();
}
}

查开一张表 datatable， dataset ，Hashtable 直接往里面赋值

update table set B=slect A from table

/*
1.利用对称密钥
搭配EncryptByKey进行数据jiami
使用DecryptByKey函数进行jiemi
这种方式比较适合大数据量
*/
CREATE SYMMETRIC KEY ZXC WITH ALGORITHM = AES_256 ENCRYPTION BY PASSWORD = 'ZXC123456'
OPEN SYMMETRIC KEY ZXC DECRYPTION BY PASSWORD = 'ZXC123456'
--jiami
SELECT Encryptbykey(Key_guid('ZXC'), 'YHDH_C')
--jiemi
SELECT CONVERT(VARCHAR(10), Decryptbykey(0x001B05DF93A12F4A941E64A06B9AEE94010000007582B2C772953F1A6ABC7298E126B76A22A6815115466653D11D6D1F23641DA6))
CLOSE SYMMETRIC KEY ZXC;
DROP SYMMETRIC KEY ZXC;

/*
2.利用非对称密钥
搭配EncryptByAsymKey进行数据jiami
使用DecryptByAsymKey函数进行jiemi
用于更高安全级别的加jiemi数据
*/
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'XIAOMA'
CREATE ASYMMETRIC KEY ABC WITH ALGORITHM=RSA_2048 ENCRYPTION BY PASSWORD = 'ZXC123456'
ALTER ASYMMETRIC KEY ABC WITH PRIVATE KEY (DECRYPTION BY PASSWORD = 'ZXC123456')
--jiami
Select Encryptbyasymkey(Asymkey_id ('ABC'), 'ZXC123456')
SELECT CONVERT(VARCHAR(100), Decryptbyasymkey (Asymkey_id('ABC'),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
DROP ASYMMETRIC KEY ABC;
DROP MASTER KEY

/*
3.利用凭证的方式
搭配EncryptByCert进行jiami
DecryptByCert函数进行jiemi
比较类似非对称密钥
*/

CREATE CERTIFICATE ZXC
ENCRYPTION BY PASSWORD = 'xiaoxiao'
WITH SUBJECT = 'DB_Encrypt_Demo Database Encryption Certificate',
START_DATE = '2015-10-1'
--jiami
Select Encryptbycert(Cert_id('ZXC'), '123456')
--jiemi
SELECT convert(Varchar(10), Decryptbycert(Cert_id('ZXC'), 0xB4E223CC08A73DE5AFE81A6FF14E76503CF55066EE8186F0781942E54B4FA97D3B49D9A16A102398311F9B259D3E2F23F0B35D3720F4AAB08357850D96A7E43494A306D227A29812BA62A33B39AC600D6585EA6B03F5F97A012C5A0BE7BC52FF60519421BD8D09311F10CC55EEA166FDBFAD2A5D9E2D3043A215AE27A918E35B,N'xiaoxiao'))
DROP CERTIFICATE ZXC;

/*
4.利用mima短语方式
搭配EncryptBypassPhrase进行jiami
使用DecryptByPassPhrase函数来jiemi
比较适合一般的数据加jiemi
*/
--jiami
Select Encryptbypassphrase('xiaoma', '123456')
--jiemi
SELECT CONVERT(VARCHAR(100), Decryptbypassphrase('xiaoma',0x01000000435DFA417C8E1A1417D901357378A1864F721EAA53DCD800 ))

例如:表a中的datetime字段都是‘2013-05-11 13:10:00‘这种格式的，筛选其中8:00到10:00之间的。
select * from 表awhere substring(convert(varchar,字段名,120),12,8) between '08:00:00' and '10:00:00'
怎么利用SQL语句查询数据库中具体某个字段的重复行？
可用group by……having来实现。
可做如下测试：
1、创建表插入数据：
create table test
(id int,name varchar(10))
insert into test values (1,'张三')
insert into test values (2,'李四')
insert into test values (3,'张三')
insert into test values (4,'王五')
insert into test values (5,'赵六')其中name是张三的有两行，也就是重复行。
2、执行sql语句如下：
select * from test where name in
(select name from test group by name having COUNT(*)1)

比较下read和readline的区别。

你这么做的意义何在？

已经不符合第一范式了。

Visible=“数据”