STRINGLESSTHAN Function

Returns true if the first string evaluates to be less than the second string, based on a set of common collation rules.

Source values can be string literals, column references, or expressions that evaluate to strings.

Wrangle vs. SQL: This function is part of Wrangle, a proprietary data transformation language. Wrangle is not SQL. For more information, see Wrangle Language.

Basic Usage

String literal reference example:

stringlessthan('a','b')

Output: Returns true since a evaluates to be less than b.

String literal reference example:

stringlessthan('a','ab')

Output: Returns true since the second string contains an additional letter.

String literal reference example:

stringlessthan('abc','x')

Output: Returns true since the first letter of the first string is less than the first letter of the second string.

Column reference example:

stringlessthan(string1,string2)

Output: Returns the evaluation of string1 column values being greater than string2 column values.

Collation refers to the organizing of written content into a standardized order. String comparison functions utilize collation rules for Latin. A summary of the rules:

Comparisons are case-sensitive.
- Uppercase letters are greater than lowercase versions of the same letter.
- However, lowercase letters that are later in the alphabet are greater than the uppercase version of the previous letter.
Two strings are equal if they match identically.
- If two strings are identical except that the second string contains one additional character at the end, the second string is greater.
A normalized version of a letter is the unaccented, lowercase version of the letter. In string comparison, it is the lowest value of all of its variants.
- a is less than ă.
- However, when compared to b, a = ă.
- The set of Latin normalized characters contains more than 26 characters.

This table illustrates some generalized rules of Latin collation.

Order	Description	Lesser Example	Greater Example
1	whitespace	(space)	(return)
2	Punctuation	'	@
3	Digits	1	2
4	Letters	a	A
5		A	b

Resources:

Anmerkung

In the following set of charts (linked below), the values at the top of the page are lower than the values listed lower on the page. Similarly, the charts listed in the left nav bar are listed in ascending order.

For more information on the applicable collation rules, see http://www.unicode.org/charts/collation/.

Syntax and Arguments

stringlessthan(string_ref1,string_ref2 <span>[,ignore_case]</span>)

Argument	Required?	Data Type	Description
string_ref1	Y	string	Name of first column or first string literal to apply to the function
string_ref2	Y	string	Name of second column or second string literal to apply to the function
ignore_case	N	string	When`true`, matching is case-insensitive. Default is`false`.

For more information on syntax standards, see Language Documentation Syntax Notes.

string_ref1, string_ref2

String literal, column reference, or expression whose elements you want to compare based on this function.

Usage Notes:

Required?	Data Type	Example Value
Yes	String literal, column reference, or expression evaluating to a string	myString1, myString2

ignore_case

When true, matches are case-insensitive. Default is false.

Anmerkung

This argument is not required. By default, matches are case-sensitive.

Required?	Data Type	Example Value
No	String literal evaluating to a Boolean	'true'

Examples

Tipp

For additional examples, see Common Tasks.

Example - Simple string comparisons

This example demonstrates functions that can be used to compare two sets of strings.

Functions:

Item	Description
STRINGGREATERTHAN Function	Returns `true` if the first string evaluates to be greater than the second string, based on a set of common collation rules.
STRINGGREATERTHANEQUAL Function	Returns `true` if the first string evaluates to be greater than or equal to the second string, based on a set of common collation rules.
STRINGLESSTHAN Function	Returns `true` if the first string evaluates to be less than the second string, based on a set of common collation rules.
STRINGLESSTHANEQUAL Function	Returns `true` if the first string evaluates to be less than or equal to the second string, based on a set of common collation rules.
EXACT Function	Returns `true` if the second string evaluates to be an exact match of the first string. Source values can be string literals, column references, or expressions that evaluate to strings.

Source:

The following table contains some example strings to be compared.

rowId	stringA	stringB
1	a	a
2	a	A
3	a	b
4	a	1
5	a	;
6	;	1
7	a	a
8	a	aa
9	abc	x

Note that in row #6, stringB begins with a space character.

Transformation:

For each set of strings, the following functions are applied to generate a new column containing the results of the comparison.

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	STRINGGREATERTHAN(stringA,stringB)
Parameter: New column name	'greaterThan'

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	STRINGGREATERTHANEQUAL(stringA,stringB)
Parameter: New column name	'greaterThanEqual'

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	STRINGLESSTHAN(stringA,stringB)
Parameter: New column name	'lessThan'

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	STRINGLESSTHANEQUAL(stringA,stringB)
Parameter: New column name	'lessThanEqual'

Transformation Name	`New formula`
Parameter: Formula type	Single row formula
Parameter: Formula	EXACT(stringA,stringB)
Parameter: New column name	'exactEqual'

Results:

In the following table, the Notes column has been added manually.


true
false
false
true
false
Aa1;
false
false
false

rowId	stringA	stringB	lessThanEqual	lessThan	greaterThanEqual	greaterThan	exactEqual	Notes
1	a	a	true	false	true	false	true	Evaluation of differences between `STRINGLESSTHAN` and `STRINGGREATERTHAN` and greater than versions.
2	a	A	true	true	false	false	false	Comparisons are case-sensitive. Uppercase letters are greater than lowercase letters.
3	a	b	true	true	false	false	`false`	Letters later in the alphabet (b) are greater than earlier letters (a).
4	a	1	false	false	true	true	`false`	Letters (a) are greater than digits (1).
5	a	;	false	false	true	true	false	Letters (a) are greater than non-alphanumerics (;).
6	;	1	true	true	false	false	false	Digits (1) are greater than non-alphanumerics (;). Therefore, the following characters are listed in order of evaluation: Aa1;
7	a	a	false	false	true	true	false	Letters (and any non-breaking character) are greater than space values.
8	a	aa	true	true	false	false	false	The second string is greater, since it contains one additional string at the end.
9	abc	x	true	true	false	false	false	The second string is greater, since its first letter is greater than the first letter of the first string.

In diesem Abschnitt:

STRINGLESSTHAN Function

Basic Usage

Syntax and Arguments

string_ref1, string_ref2

ignore_case

Examples

Example - Simple string comparisons

Suchresultat