The SQL standard specifies a large number of keywords which may not be used as the names of tables, indices, columns, databases, user-defined functions, collations, virtual table modules, or any other named object. The list of keywords is so long that few people can remember them all. For most SQL code, your safest bet is to never use any English language word as the name of a user-defined object.
If you want to use a keyword as a name, you need to quote it. There are four ways of quoting keywords in SQLite:
'keyword' A keyword in single quotes is a string literal. "keyword" A keyword in double-quotes is an identifier. [keyword] A keyword enclosed in square brackets is an identifier. This is not standard SQL. This quoting mechanism is used by MS Access and SQL Server and is included in SQLite for compatibility. `keyword` A keyword enclosed in grave accents (ASCII code 96) is an identifier. This is not standard SQL. This quoting mechanism is used by MySQL and is included in SQLite for compatibility.
For resilience when confronted with historical SQL statements, SQLite will sometimes bend the quoting rules above:
If a keyword in single quotes (ex: 'key' or 'glob') is used in a context where an identifier is allowed but where a string literal is not allowed, then the token is understood to be an identifier instead of a string literal.
If a keyword in double quotes (ex: "key" or "glob") is used in a context where it cannot be resolved to an identifier but where a string literal is allowed, then the token is understood to be a string literal instead of an identifier.
Programmers are cautioned not to use the two exceptions described in the previous bullets. We emphasize that they exist only so that old and ill-formed SQL statements will run correctly. Future versions of SQLite might raise errors instead of accepting the malformed statements covered by the exceptions above.
SQLite adds new keywords from time to time when it takes on new features. So to prevent your code from being broken by future enhancements, you should normally quote any identifier that is an English language word, even if you do not have to.
The list below shows all possible keywords used by any build of SQLite regardless of compile-time options. Most reasonable configurations use most or all of these keywords, but some keywords may be omitted when SQL language features are disabled. Applications can use the sqlite3_keyword_count(), sqlite3_keyword_name(), and sqlite3_keyword_check() interfaces to determine the keywords recognized by SQLite at run-time. Regardless of the compile-time configuration, any identifier that is not on the following 147 element list is not a keyword to the SQL parser in SQLite:
This page last modified on 2021-03-15 12:20:17 UTC