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private void btnNew_Click(object sender, EventArgs e)
       {

           sql = " SELECT  br.`AccessionNo`, `BookTitle`, `BookDesc` as Description,Concat (`Firstname`,' ', `Lastname`) as 'Borrower',`NoCopies`, `DateBorrowed`, `DueDate` FROM `Borrow` br,`Books` b,`Student` bw  WHERE br.AccessionNo=b.AccessionNo AND br.`BorrowerId`=bw.`BorrowerId` ORDER BY BorrowId Desc";
           Load_ResultList(sql, dtg_BlistOfBooks);
           ExecuteQuery(sql);
           LoadData();

           sql = "SELECT AccessionNo From books Where Status = 'Available'";
           autocomplete(sql, txtAccesionNumBorrow);
           LoadData1();

           sql = "SELECT BorrowerId From Student";
           autocomplete(sql, txtBorrowerId);
           LoadData2();
       }


What I have tried:

I use the || concatenation operator but still error
Posted
Updated 8hrs ago
v2

1 solution

Most likely, you need to use a JOIN to combine the table information rather than trying to just reference multiple tables.

The problem is that SELECT ... FROM Table1, Table2 combines all row combinations: for three rows in each table there are 9 output rows.

A JOIN allows you to use the DB's relational properties and return three rows of related info:
SELECT * FROM Table1 t1
JOIN Table2 t2 ON t1.ID = t2.ID
See here: SQL Joins[^]
   

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