Keywords and Reserved Words •Loadable functions and stored functions Loadable functions and stored functions share the same namespace, so you cannot create a loadable function and a stored function with the same name. The preceding function name resolution rules have implications for upgrading to versions of MySQL that implement new built-in functions: •If you have already created a loadable function with a given name and upgrade MySQL to a version that implements a new built-in function with the same name, the loadable function becomes inaccessible. To correct this, use  DROP FUNCTION  to drop the loadable function and  CREATE FUNCTION  to re-create the loadable function with a different nonconflicting name. Then modify any affected code to use the new name. •If a new version of MySQL implements a built-in function with the same name as an existing stored function, you have two choices: Rename the stored function to use a nonconflicting name, or change calls to the function so that they use a schema qualifier (that is, use  schema_name . func_name () syntax). In either case, modify any affected code accordingly. Keywords are words that have significance in SQL. Certain keywords, such as  SELECT ,  DELETE , or BIGINT , are reserved and require special treatment for use as identifiers such as table and column names. This may also be true for the names of built-in functions. Nonreserved keywords are permitted as identifiers without quoting. Reserved words are permitted as identifiers if you quote them as described in Section 9.2, “Schema Object Names” : BEGIN  and  END  are keywords but not reserved, so their use as identifiers does not require quoting. INTERVAL  is a reserved keyword and must be quoted to be used as an identifier: mysql>  CREATE TABLE interval (begin INT, end INT); ERROR 1064 (42000): You have an error in your SQL syntax ... near ’interval (begin INT, end INT)’ 9.3 Keywords and Reserved Words mysql>  CREATE TABLE ‘interval‘ (begin INT, end INT); Query OK, 0 rows affected (0.01 sec) mysql>  CREATE TABLE mydb.interval (begin INT, end INT); Query OK, 0 rows affected (0.01 sec) Exception: A word that follows a period in a qualified name must be an identifier, so it need not be quoted even if it is reserved: Names of built-in functions are permitted as identifiers but may require care to be used as such. For example,  COUNT  is acceptable as a column name. However, by default, no whitespace is permitted in function invocations between the function name and the following  (  character. This requirement enables the parser to distinguish whether the name is used in a function call or in nonfunction context. For further details on recognition of function names, see Section 9.2.5, “Function Name Parsing and Resolution” . The  INFORMATION_SCHEMA.KEYWORDS  table lists the words considered keywords by MySQL and indicates whether they are reserved. See Section 26.3.17, “The INFORMATION_SCHEMA KEYWORDS Table” . •MySQL 8.0 Keywords and Reserved Words •MySQL 8.0 New Keywords and Reserved Words 1880