Quote¶

Overview¶

The Quote expression adds single quotes around a string value, escaping any existing single quotes within the string by doubling them. This expression is commonly used for preparing string literals for SQL contexts or for display purposes where quoted strings are needed.

Syntax¶

quote(string_expr)

// DataFrame API
import org.apache.spark.sql.functions._
df.select(quote($"column_name"))

Arguments¶

Argument	Type	Description
input	StringType	The string expression to be quoted

Return Type¶

StringType - Returns a string with single quotes added around the input value.

Supported Data Types¶

StringType with collation support
Supports trim collation semantics
Input values are implicitly cast to string if needed

Algorithm¶

Wraps the input string with single quotes at the beginning and end
Scans the input string for existing single quote characters
Doubles any existing single quotes within the string to escape them properly
Returns the properly quoted and escaped string result
Handles null inputs by returning null

Partitioning Behavior¶

This expression preserves partitioning behavior:

Does not require data shuffle as it operates on individual rows
Maintains the same partitioning scheme as the input
Can be safely pushed down to individual partitions

Edge Cases¶

Null handling: Returns null when input is null (nullable = true)
Empty string: Returns two single quotes ('') for empty input
String with quotes: Existing single quotes are escaped by doubling them
Special characters: All other special characters are preserved as-is within the quotes

Code Generation¶

This expression uses RuntimeReplaceable pattern:

Delegates actual execution to ExpressionImplUtils.quote() method via StaticInvoke
Benefits from Catalyst's code generation optimizations through the static method call
Supports context-independent constant folding when input is foldable

Examples¶

SELECT quote('Hello World');
-- Result: 'Hello World'

SELECT quote('Don\'t');  
-- Result: 'Don''t'

SELECT quote('');
-- Result: ''

SELECT quote(NULL);
-- Result: NULL

// DataFrame API usage
import org.apache.spark.sql.functions._

df.select(quote(col("message")))
df.withColumn("quoted_text", quote($"original_text"))

// With literal values
df.select(quote(lit("Hello World")))