SQlcharindex命令

用与提出'_'号左右值

select  right('b_s',charindex( '_','b_s')-1) ;
select  left('b_s',charindex( '_','b_s')-1) ;

 select  left('b_s',charindex( '_','b_s')-1) as [name]  from b13 where zzh=1 ; // as［name］为列名

select case when charindex('_',nnn)>0 then left(nnn,charindex('_',nnn)-1)
else nnn end
from b13

select left(nnn,charindex('_',nnn)-1),right(nnn,len(nnn)-charindex('_',nnn)+1)
from b13
where charindex('_',nnn)>0

SELECT (a.nnn+b.aaa) tx,(a.nnn+b.aaa) ty
FROM b13 a
LEFT JOIN a15 b on (a.zzh=b.zzh)

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private void button2_Click(object sender, EventArgs e)
        {
            string zzh = textBox1.Text.Trim().ToString();
            string strConnection = "user id=sa;password=;";
            strConnection += "database = pubs;server=CHINESE-D834096";
            //strConnection += "Connect Timeout=30";
            string SelectOneStr = "select nnn from b13 where zzh='" + zzh + "'";
            SqlConnection Sqlcon = new SqlConnection(strConnection);
            SqlCommand Sqlcom = new SqlCommand(SelectOneStr, Sqlcon);
            Sqlcon.Open();
            SqlDataReader dbRead = Sqlcom.ExecuteReader();

 

            if (dbRead.Read())
            {

                string qqq = dbRead["nnn"].ToString();
                dbRead.Close();
               

                string SelectOneStr1 = "select  left('" +qqq+ "',charindex( '_','"+qqq+"')-1) as [name1] from b13 where zzh=1";
                SqlConnection Sqlcon1 = new SqlConnection(strConnection);
                SqlCommand Sqlcom1 = new SqlCommand(SelectOneStr1, Sqlcon1);
                Sqlcon1.Open();
                SqlDataReader dbRead1 = Sqlcom1.ExecuteReader();

                if (dbRead1.Read())
                {
                    string wwq = dbRead1["name1"].ToString();
                    //textBox3.Text = wwq;
                }

            }
            string SelectOneStr2 = "select aaa from a15 where zzh='" + zzh + "'";
            SqlConnection Sqlcon2 = new SqlConnection(strConnection);
            SqlCommand Sqlcom2 = new SqlCommand(SelectOneStr2, Sqlcon2);
            Sqlcon2.Open();
            SqlDataReader dbRead2 = Sqlcom2.ExecuteReader();
            if (dbRead2.Read())
            {

                string vvv = dbRead2["aaa"].ToString();
                dbRead2.Close();

                string SelectOneStr4 = "select  left('" +vvv+ "',charindex( ',','" +vvv+ "')-1) as [name2] from a15 where zzh=1";
                SqlConnection Sqlcon4 = new SqlConnection(strConnection);
                SqlCommand Sqlcom4 = new SqlCommand(SelectOneStr4, Sqlcon4);
                Sqlcon4.Open();
                SqlDataReader dbRead4 = Sqlcom4.ExecuteReader();

                if (dbRead4.Read())
                {
                    string wwa = dbRead4["name2"].ToString();
                    textBox3.Text = wwa;
                }

            }
        
          
            //select  right('b_s',charindex( '_','b_s')-1) ;
            //select  left('b_s',charindex( '_','b_s')-1) ;
          
        }