Question

I have 300 boolean fields in one table, and I’m trying to do something like this:

One string field:

10000010000100100100100100010001

Here’s a simple way to do a simple search of this field like:

select * from table where field  xor "10000010000100100100000000010001"

I’m trying this but is to long:

select * from test where mid(info,2,1) and mid(info,3,1)

🙂 Help!!

Answer 1

A citation from the book High Performance MySQL:

If you used an integer, you could write that example as follows:

mysql> SET @CAN_READ   := 1 << 0,
    -> @CAN_WRITE  := 1 << 1,
    -> @CAN_DELETE := 1 << 2;
mysql> CREATE TABLE acl (
    -> perms TINYINT UNSIGNED NOT NULL DEFAULT 0
    -> );
mysql> INSERT INTO acl(perms) VALUES(@CAN_READ + @CAN_DELETE);
mysql> SELECT perms FROM acl WHERE perms & @CAN_READ;
+-------+
| perms |
+-------+
|   5   |
+-------+

UPD:

A possible solution in your case if all the strings are of the same length (I’ll be surprised if they are not):

select * from teste where info like '_______00001001001001001___1___1';