c#

[xsf0515]

一个winform界面，上面输入姓名，或者学号，点击查询时就会在下面DataGridview中显示数据，因为where条件没写，所以查询的是所有记录
请问怎样写代码当我输入学号或者姓名时查询出对应的一条数据，而不是整个数据，下面是我写的一段，请教各位
if(textBox1.Text.Trim()!=""&&textBox1.Text.Trim()!=null)
{
if (sql != null)
{
sql +="and s.Stu_Name='"+textBox1.Text.Trim()+"'";
}
else
{
sql += "s.Stu_Name='" + textBox1.Text.Trim() + "'";
}
}
if (textBox2.Text.Trim() != "" && textBox2.Text.Trim() != null)
{
if (sql != null)
{
sql += "and s.Stu_ID='" + textBox2.Text.Trim() + "'";
}
else
{
sql += "s.Stu_ID='" + textBox2.Text.Trim() + "'";
}
}

[ttllxx]

select 后加 top 1

[orochiheart]

select * from 表 where 名字='小明'
select * from 表 where 学号='123

[orochiheart]

select * from 表 where 名字='小明' or 学号=123
select * from 表 where 名字='小明' and 学号=123

你的需求一般就是四种情况吧

[orochiheart]

select * from 表 where 学号='123
=》
select * from 表 where 学号=123

[xsf0515]

where后面的条件总不能我要查询某一个改一下条件吧，多麻烦啊

[orochiheart]

你写的好乱啊 帮你整理下代码

string sql = "";
if (textBox1.Text.Trim() != "" && textBox2.Text.Trim() =="")
{
if (sql != null)
{
sql += "and s.Stu_Name='" + textBox1.Text.Trim() + "'";
}
}
if (textBox2.Text.Trim() != "" && textBox1.Text.Trim() == "")
{
if (sql != null)
{
sql += "and s.Stu_ID='" + textBox2.Text.Trim() + "'";
}
}
else if (textBox2.Text.Trim() != "" && textBox2.Text.Trim() != "")
{
if (sql != null)
{
sql += "and s.Stu_ID='" + textBox2.Text.Trim() + "' and s.Stu_Name=" + textBox1.Text.Trim();
}
}

[orochiheart]

                if (sql != null)
                {
                    sql += "and s.Stu_Name='" + textBox1.Text.Trim() + "'";
                }
            }
            if (textBox2.Text.Trim() != "" && textBox1.Text.Trim() == "")
            {
                if (sql != null)
                {
                    sql += "and s.Stu_ID='" + textBox2.Text.Trim() + "'";
                }
            }
            else if (textBox2.Text.Trim() != ""  &&  textBox2.Text.Trim() != "")
            {
                if (sql != null)
                {
                    sql += "and s.Stu_ID='" + textBox2.Text.Trim() + "' and s.Stu_Name=" + textBox1.Text.Trim();
                }
            }

[orochiheart]

发错了

            string sql = "";
            if (textBox1.Text.Trim() != "" && textBox2.Text.Trim() =="")
            {
                if (sql != null)
                {
                    sql += "and s.Stu_Name='" + textBox1.Text.Trim() + "'";
                }
            }
            if (textBox2.Text.Trim() != "" && textBox1.Text.Trim() == "")
            {
                if (sql != null)
                {
                    sql += "and s.Stu_ID='" + textBox2.Text.Trim() + "'";
                }
            }
            else if (textBox2.Text.Trim() != ""  &&  textBox2.Text.Trim() != "")
            {
                if (sql != null)
                {
                    sql += "and s.Stu_ID='" + textBox2.Text.Trim() + "' and s.Stu_Name=" + textBox1.Text.Trim();
                }
            }

[xsf0515]

没用啊还是显示的全部信息

[orochiheart]

你把你全部代码贴出来

[orochiheart]

你设个断点 看sql语句调试看看吧

[Csharp_琪]

这个确实是sql语句的问题，试着用字符串拼接的方法，吧参数传进sql语句，不会很难的

[xsf0515]

private void button1_Click(object sender, EventArgs e)
{

string sql = "";
if (textBox1.Text.Trim() != "" && textBox2.Text.Trim() == "")
{
if (sql != null)
{
sql += "and s.Stu_Name='" + textBox1.Text.Trim() + "'";
}
}
if (textBox2.Text.Trim() != "" && textBox1.Text.Trim() == "")
{
if (sql != null)
{
sql += "and s.Stu_ID='" + textBox2.Text.Trim() + "'";
}
}
else if (textBox2.Text.Trim() != "" && textBox2.Text.Trim() != "")
{
if (sql != null)
{
sql += "and s.Stu_ID='" + textBox2.Text.Trim() + "' and s.Stu_Name=" + textBox1.Text.Trim();
}
}

ds = null;
sqlconn.SQL = "select p.ID as ID,Stu_Name,s.Stu_ID as Stu_ID ,p1.Pay_Name as Pay_Name ,c.Code_Name as Code_Name ,p.Remarks as Remarks from Pay p left join Student_Info s on p.Stu_ID=s.Stu_ID left join Pay_Info p1 on p.Pay_ID=p1.Pay_ID left join CodeMaster c on p.State=c.Code_No and c.Code_Type='102'";
ds = sqlconn.ReturnDataSet();
dataGridView1.DataSource = ds.Tables[0];
}

[orochiheart]

你拼接后的sql在最后也没用啊 这样下就行了

        private void button1_Click(object sender, EventArgs e)
        {
            string sql = "";
            if (textBox1.Text.Trim() != "" && textBox2.Text.Trim() == "")
            {
                if (sql != null)
                {
                    sql += " s.Stu_Name='" + textBox1.Text.Trim() + "'";
                }
            }
            if (textBox2.Text.Trim() != "" && textBox1.Text.Trim() == "")
            {
                if (sql != null)
                {
                    sql += " s.Stu_ID='" + textBox2.Text.Trim() + "'";
                }
            }
            else if (textBox2.Text.Trim() != "" && textBox2.Text.Trim() != "")
            {
                if (sql != null)
                {
                    sql += " s.Stu_ID='" + textBox2.Text.Trim() + "' and s.Stu_Name=" + textBox1.Text.Trim();
                }
            }
              
            ds = null;
            sqlconn.SQL = "select p.ID as ID,Stu_Name,s.Stu_ID as Stu_ID ,p1.Pay_Name as Pay_Name ,c.Code_Name as Code_Name ,p.Remarks as Remarks from Pay p left join Student_Info s on p.Stu_ID=s.Stu_ID left join Pay_Info p1 on p.Pay_ID=p1.Pay_ID left join CodeMaster c on p.State=c.Code_No and c.Code_Type='102' where " +sql;
            ds = sqlconn.ReturnDataSet();
            dataGridView1.DataSource = ds.Tables[0];

        }

[orochiheart]

第三个else if写错了 应该是->
else if (textBox1.Text.Trim() != "" && textBox2.Text.Trim() != "")
{
if (sql != null)
{
sql += " s.Stu_ID='" + textBox2.Text.Trim() + "' and s.Stu_Name=" + textBox1.Text.Trim();
}
}