（PHP，SQL）当使用Insert Into .. Select语句时，我得到两次相同的行
问题描述：
I want to take some data from Tovar_Dosky into Filter1 where value of column "cena" is less or equal to 50. In table Filter1 I gethave only 1 row. But I get that row twice. Any help ? Code:
$sql= "INSERT INTO Filter1(meno, znacka, cena, op, format)
SELECT meno, znacka, cena, op, format
FROM Tovar_Dosky WHERE cena<=50";
$result=$conn->query($sql);
if (!($conn->query($sql) === TRUE)) {
echo "Error: " .$conn->error;
}
I get no errors from sql.
答
Yes, Its obvious you are executing the query twice ... Better change your query to below ...
$sql= "INSERT INTO Filter1(meno, znacka, cena, op, format)
SELECT meno, znacka, cena, op, format
FROM Tovar_Dosky WHERE cena<=50";
if ($result=$conn->query($sql)) {
//Do what you want with the $result
}
else{
echo "Error: " .$conn->error;
}