检查mysql db中是否已存在

问题描述

大家好我想检查我的表中是否已经存在文本如果存在不插入且如果不存在则插入它



i write命令只是为了插入我不知道在插入之前如何检查

hi guys i want to check if text already exist in my table if exist don't insert and if doesn't exist insert it

i wrote command just to insert i don't know how to check before inserting

MySqlConnection conect = new MySqlConnection(connectionString);
                conect.Open();
                MySqlCommand cmsd = con.CreateCommand();
                cmd.CommandType = CommandType.Text;
                lochwidTxt.Text = HWDI.GetMachineGuid();
                cmd.CommandText = "INSERT INTO userprof  (u_name, u_pass, u_ip) " + " Values ('" + textBox1.Text + "', '" + textBox2.Text + "', '" + lochwidTxt.Text + "')";

我尝试过：



检查是否已存在（如果它不存在）插入

What I have tried:

check if already exist if it doesn't exist insert it

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