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The words in the following table are explicitly reserved in EPL, however certain keywords are allowed as event property names in expressions and as column names in the rename syntax of the select clause.
Most of the words in the table are forbidden by standard SQL as well. A few are reserved because EPL needs them.
Names of built-in functions and certain auxiliary keywords are permitted as identifiers for use either as event property names in expressions and for the column rename syntax. The second column in the table below indicates which keywords are acceptable. For example, count is acceptable.
An example of permitted use is:
select last, count(*) as count from MyEvent
This example shows an incorrect use of a reserved keyword:
// incorrect select insert from MyEvent
The table of explicitly reserved keywords and permitted keywords:
Table B.1. Reserved Keywords
| Keyword | Property Name and Rename Syntax |
|---|---|
| after | - |
| all | - |
| and | - |
| as | - |
| at | yes |
| asc | - |
| avedev | yes |
| avg | yes |
| between | - |
| by | - |
| case | - |
| cast | yes |
| coalesce | yes |
| context | - |
| count | yes |
| create | - |
| current_timestamp | - |
| dataflow | - |
| day | - |
| days | - |
| delete | - |
| define | yes |
| desc | - |
| distinct | - |
| else | - |
| end | - |
| escape | yes |
| events | yes |
| every | yes |
| exists | - |
| expression | - |
| false | yes |
| first | yes |
| for | yes |
| from | - |
| full | yes |
| group | - |
| having | - |
| hour | - |
| hours | - |
| in | - |
| initiated | - |
| inner | - |
| insert | - |
| instanceof | yes |
| into | - |
| irstream | - |
| is | - |
| istream | - |
| join | yes |
| last | yes |
| lastweekday | yes |
| left | yes |
| limit | - |
| like | - |
| max | yes |
| match_recognize | - |
| matched | - |
| matches | - |
| median | yes |
| measures | yes |
| merge | - |
| metadatasql | yes |
| min | yes |
| minute | yes |
| minutes | yes |
| msec | yes |
| millisecond | yes |
| milliseconds | yes |
| new | - |
| not | - |
| null | - |
| offset | - |
| on | - |
| or | - |
| order | - |
| outer | yes |
| output | - |
| partition | - |
| pattern | yes |
| prev | yes |
| prior | yes |
| regexp | - |
| retain-union | yes |
| retain-intersection | yes |
| right | yes |
| rstream | - |
| sec | - |
| second | - |
| seconds | - |
| select | - |
| set | - |
| some | - |
| snapshot | yes |
| sql | yes |
| start | - |
| stddev | yes |
| sum | yes |
| terminated | - |
| then | - |
| true | - |
| unidirectional | yes |
| until | yes |
| update | - |
| using | yes |
| variable | yes |
| weekday | yes |
| when | - |
| where | - |
| while | - |
| window | yes |