Selecting a column that is also a keyword in MySQL

Question

For some reason, the developers at a new company I\'m working for decided to name their columns \"ignore\" and \"exists\". Now when I run MySQL queries with those words in t

Answer 1

The official term is "idiocy" :-) You can put backticks around the names such as

`ignore`

but I would give serious consideration to changing the names if possible. Backticks are not standard SQL, and I prefer my column names to be a little more expressive. For example, ignoreThisUser or orderExists (the general rule I try to follow is to have a noun and a verb in there somewhere).

Interestingly, some DBMS' can figure out not to treat it as a reserved word based on context. For example, DB2/z allows the rather hideous:

> CREATE TABLE SELECT ( SELECT VARCHAR(10) );
> INSERT INTO SELECT VALUES ('HELLO');
> SELECT SELECT FROM SELECT;
SELECT
---------+---------+---------+--------
HELLO
DSNE610I NUMBER OF ROWS DISPLAYED IS 1

Answer 2

put the names in backticks:

`ignore`, `exists`

If you're working across multiple tables or databases you need to escape the database name, table name, and field name separately (if each matches a keyword):

SELECT * FROM `db1`.`table1`
LEFT JOIN `db2`.`table2` on `db1`.`table1`.`field1`=`db2`.`table2`.`field2`

Only the portions that actually match a keyword have to be escaped, so things like:

select * from `db1`.table

are ok too.