# Reserved Keywords

Acho is a SQL-based [RDBMS](https://acho.io/glossary/relational-database). When applying actions such as [Formula](https://docs.acho.io/applying-actions#09-formula) and [Rename](https://docs.acho.io/applying-actions#14-rename) please **avoid** using "reserved keywords" when creating or naming a column. These keywords are synonymous with some of the SQL operators and therefore cannot be used for column names. 

These keywords are:

|                        |           |           |           |             |
| ---------------------- | --------- | --------- | --------- | ----------- |
| AND                    | DISTINCT  | IF        | NULLS     | TABLESAMPLE |
| ANY                    | ELSE      | IGNORE    | OF        | THEN        |
| ARRAY                  | END       | IN        | ON        | TO          |
| AS                     | ENUM      | INNER     | OR        | TREAT       |
| ASC                    | ESCAPE    | INTERSECT | ORDER     | TRUE        |
| ASSERT\_ROWS\_MODIFIED | EXCEPT    | INTERVAL  | OUTER     | UNBOUNDED   |
| AT                     | EXCLUDE   | INTO      | OVER      | UNION       |
| BETWEEN                | EXISTS    | IS        | PARTITION | UNNEST      |
| BY                     | EXTRACT   | JOIN      | PRECEDING | USING       |
| CASE                   | FALSE     | LATERAL   | PROTO     | WHEN        |
| CAST                   | FETCH     | LEFT      | RANGE     | WHERE       |
| COLLATE                | FOLLOWING | LIKE      | RECURSIVE | WINDOW      |
| CONTAINS               | FOR       | LIMIT     | RESPECT   | WITH        |
| CREATE                 | FROM      | LOOKUP    | RIGHT     | WITHIN      |
| CROSS                  | FULL      | MERGE     | ROLLUP    |             |
| CUBE                   | GROUP     | NATURAL   | ROWS      |             |
| CURRENT                | GROUPING  | NEW       | SELECT    |             |
| DEFAULT                | GROUPS    | NO        | SET       |             |
| DEFINE                 | HASH      | NOT       | SOME      |             |