Identifiers

An identifier is a string used to identify a database object such as a table, view, schema, or column. Spark SQL has regular identifiers and delimited identifiers, which are enclosed within backticks. Both regular identifiers and delimited identifiers are case-insensitive.

Syntax

Regular identifiers

{ letter | digit | '_' } [ , ... ]

Note

If spark.sql.ansi.enabled is set to true, you cannot use an ANSI SQL reserved keyword as an identifier.

Delimited identifiers

`c [ , ... ]`

Parameters

• letter: Any letter from A-Z or a-z.
• digit: Any numeral from 0 to 9.
• c: Any character from the character set. Use ` to escape special characters (for example, `.` ).

Examples

-- This CREATE TABLE fails with ParseException because of the illegal identifier name a.b
CREATE TABLE test (a.b int);
org.apache.spark.sql.catalyst.parser.ParseException:
no viable alternative at input 'CREATE TABLE test (a.'(line 1, pos 20)

-- This CREATE TABLE works
CREATE TABLE test (`a.b` int);

-- This CREATE TABLE fails with ParseException because special character ` is not escaped
CREATE TABLE test1 (`a`b` int);
org.apache.spark.sql.catalyst.parser.ParseException:
no viable alternative at input 'CREATE TABLE test (`a`b`'(line 1, pos 23)

-- This CREATE TABLE works
CREATE TABLE test (`a``b` int);