如何在select mysql语法中使用2个表？ [英] How to i use 2 tables on a select mysql syntax?

问题描述

您好，



我有这段代码，它显示我的sql查询字符串，但我如何设置查询以显示来自2个表的数据？（entradas，sayas）

Hello,

I have this piece of code, where it shows my sql query string, but how can i setup the query to show the data from 2 tables?(entradas,saidas)

string SQL = "SELECT FROM entradas,saidas(entradas.(id_veiculo,id_empresa,nome_condutor,empresa_visitante,empresa_visitar,visitado,ncartao,data,hora,obs,sector), saidas.(DATA,HORA,OBS)) WHERE id_empresa = @tabempresa; ";

using (var cn = new MySqlConnection("server=localhost;user id=root;password=12345;persistsecurityinfo=True;database=portaria;allowuservariables=True"))
{
    using (var cmd = new MySqlCommand(SQL, cn))
    {
        cmd.Parameters.AddWithValue("@tabempresa", tabControl1.SelectedIndex);
        MySqlDataAdapter sda = new MySqlDataAdapter();
        DataTable dt = new DataTable();
        sda.SelectCommand = cmd;
        sda.Fill(dt);
        cn.Open();

        try
        {
            DataView dv = new DataView(dt);
            Grid1.DataSource = dv.Table;
            Grid1.AutoGenerateColumns = true;
            cmd.ExecuteNonQuery();
        }
        catch (MySqlException ex)
        {
            // Do some logging or something.
            MessageBox.Show("There was an error accessing your data. DETAIL: " + ex.ToString());
        }
        cn.Close();
    }
}

我尝试了什么： < br $>


尝试使用普通的select语法在一个数据网格上显示两个表。

What I have tried:

tried to use normal select syntax to show up both tables on one datagrid.

推荐答案

将查询更改为：

Change query to:

SELECT * FROM entradas a LEFT OUTER JOIN saidas b
ON a.data = b.data AND a.hora=b.hora and a.sector = b.sector
WHERE id_empresa = @tabempresa;

NAMED：

NAMED:

SELECT a.id_veiculo, a.id_empresa, a.nome_condutor, a.empresa_visitante, a.empresa_visitar, a.visitado, a.ncartao, a.data, a.hora, a.obs,a.sector, b.data as Data1, b.hora as hora1 FROM entradas a LEFT OUTER JOIN saidas b
ON a.data = b.data AND a.hora=b.hora and a.sector = b.sector
WHERE id_empresa = @tabempresa;

这篇关于如何在select mysql语法中使用2个表？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！