更改表SQL PHP

Question

I'm just trying to insert two variables into a table to create two new columns. I can get one variable inserting fine and creating a new column, but struggling to get the right syntax for the second one. This currently works:

mysqli_query($link,"ALTER TABLE importantdetails.extracols ADD  `" . $newCol1 . "` VARCHAR(100)");

However I can't get $newCol2 to insert. I've tried everything I can think of.

Any ideas?

Thanks

Answer 1

To add multiple columns to an existing table, the SQL ALTER TABLE syntax is:

ALTER TABLE table_name
  ADD (column_1 column-definition,
    column_2 column-definition,
    ...
    column_n column_definition);

 Ex. ALTER TABLE supplier
    ADD (supplier_name varchar(50),
       city varchar(45));

Answer 2

如果您有$link无需添加数据库名称importantdetails尝试

mysqli_query($link,"ALTER TABLE extracols ADD (".$newCol1." VARCHAR(100),  ".$newCol2." VARCHAR(100))");

Answer 3

Make sure $newCol2 is not a MySQL reserved word and that you set its type correctly. If it's also a VARCHAR(100), the only problem I can think of is that $newCol2 is a reserved word.

If you're trying to add multiple columns in one ALTER command, you could do it like this:

mysqli_query($link,"ALTER TABLE importantdetails.extracols ADD ('$col1' col1_def, '$col2' col2_def));

Answer 4

The syntax should be

mysqli_query($link,"ALTER TABLE importantdetails.extracols ADD  ('".$newCol1."' VARCHAR(100),  '".$newCol2."' VARCHAR(100))");

Assuming $newCol2 contains the string name of your new column and you want this column to be of type varchar(100)