Can I use DataTable for SQL difference?

froginwell

public DataSet aaa (DataTable dt)
{
    string sql = "select a. *, b. * from tba left join" + dt + "b on a.id = b.id";
}
It doesn't work like this

mopalex

I can tell you responsibly: no

froginwell

I do n’t know. I want to achieve this effect. How should I do it?

我爱圣骑士

You can use DataTable.Name if you get the name of the DataTable consistent with the database, but the DataTable and the table in the database are not the same thing, it is best not to use this.

froginwell

What I want is to connect the DataTable to the Table in the database.
Wrong written above
 string sql = "select a. *, b. * from sqltb a left join" + dt + "b on a.id = b.id";

sqltb is the table in the database, dt is the DataTable difference

57162356

You can first fill the database table into the datatable
Combine these two datatables

shygza

Create a temporary table with the same name directly in the database, import the interface data into the temporary table and then join the query, but this is really stupid and the performance is super poor. The Merge effect of the DataSet is not very good, although the structure is merged, but the data It also turned up and was not easy to handle.
Or let's deal with the interface step by step with filtering.

froginwell

sqltb is a table in ms sql, DataTable is the number found from my sql, it is annoying to combine the two.

shygza

Since the DataTable is the number found from my sql, if there is no modification operation to the DataTable in the interface, you can rebuild the sql statement query in the form of a subquery, and use the result of the query number as the subtable of the new statement.

string sql = "select a. *, b. * from sqltb a left join (here is the sql statement for the number of queries) b on a.id = b.id";

qwer000

as follows
If you set a name for DT

string sql = "select a. *, b. * from sqltb a left join" + dt.tablename + "b on a.id = b.id";