C# SQL Select from multiple tables

Henrik Visby

Hey C# Corner,

I have the following line:

minDat = new SqlCommand("SELECT * FROM Data WHERE (FileName like '%.html' or FileName like '%.htm') and ocrconvert = 0", cnn).ExecuteReader();

I want to SELECT * FROM Data and TestTable

So is is possible in that line to make it able to select everything from multiple tables?

Best regards

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Dhanunjay Jajimoggla12y ago
string sqlSelect = "SELECT * FROM Data;" +
"SELECT * FROM Data1";

OR

command.CommandText = "SELECT * FROM Data;; SELECT * FROM Data1";
Rasmita Dash12y ago
SELECT * FROM Data,TestTable

which will give you (no. of records in Data * no. of records in TestTable) records. which has very limited usage. Instead if you want to get data from these tables you can use union. For union your selected columns of both tables should have same data type.

If I have Table_1 as

id name
10 1_nam10
11 1_nam11

& Table_2 as
id name address
20 2_nam20 addrs
21 2_nam21 addrs

then I can use
select id, name from Table_1 union select id, name from Table_2
This is what probably you want.

id	name
10	1_nam10
11	1_nam11

id	name	address
20	2_nam20	addrs
21	2_nam21	addrs