String Functions¶
Summary¶
| Function | Description |
|---|---|
toUpper(str) / upper(str) |
Convert to uppercase |
toLower(str) / lower(str) |
Convert to lowercase |
trim(str) |
Remove leading/trailing whitespace |
TRIM(BOTH\|LEADING\|TRAILING 'chars' FROM str) |
Trim specific characters |
ltrim(str) |
Remove leading whitespace |
rtrim(str) |
Remove trailing whitespace |
substring(str, start, len) |
Extract substring |
char_length(str) |
Character count |
octet_length(str) |
Byte length (UTF-8) |
replace(str, search, repl) |
Replace occurrences |
split(str, delim) |
Split into list |
left(str, n) |
First n characters |
right(str, n) |
Last n characters |
reverse(str) |
Reverse characters |
normalize(str) |
Unicode normalization |
string_join(list, sep) |
Join list into string |
toString(expr) |
Convert to string |
Case Conversion¶
RETURN toUpper('hello') -- 'HELLO'
RETURN upper('hello') -- 'HELLO'
RETURN toLower('HELLO') -- 'hello'
RETURN lower('HELLO') -- 'hello'
Trimming¶
RETURN trim(' hello ') -- 'hello'
RETURN ltrim(' hello ') -- 'hello '
RETURN rtrim(' hello ') -- ' hello'
-- ISO enhanced TRIM with trim specification (GF05)
RETURN TRIM(BOTH 'xy' FROM 'xxyhelloxyy') -- 'hello'
RETURN TRIM(LEADING '0' FROM '000123') -- '123'
RETURN TRIM(TRAILING '.' FROM 'hello...') -- 'hello'
Substring and Length¶
-- Extract substring: substring(string, start, length)
-- Start is 0-based
RETURN substring('hello world', 0, 5) -- 'hello'
RETURN substring('hello world', 6, 5) -- 'world'
-- Character count
RETURN char_length('hello') -- 5
RETURN charlength('hello') -- 5 (alias)
-- Byte length (differs from char_length for multibyte characters)
RETURN octet_length('hello') -- 5
RETURN octet_length('café') -- 5 (UTF-8: é is 2 bytes)
Search and Replace¶
-- Replace all occurrences
RETURN replace('hello world', 'world', 'GQL') -- 'hello GQL'
-- Split into a list
RETURN split('a,b,c', ',') -- ['a', 'b', 'c']
-- Practical: split and process tags
MATCH (p:Post)
UNWIND split(p.tags, ',') AS tag
RETURN trim(tag), count(*) AS usage
ORDER BY usage DESC
Extraction¶
-- First n characters
RETURN left('hello world', 5) -- 'hello'
-- Last n characters
RETURN right('hello world', 5) -- 'world'
Transformation¶
RETURN reverse('hello') -- 'olleh'
-- Unicode normalization (identity for UTF-8 strings)
RETURN normalize('café') -- 'café'
String Joining¶
Join a list of strings with a separator:
RETURN string_join(['Alix', 'Gus', 'Harm'], ', ')
-- 'Alix, Gus, Harm'
-- Practical: collect names and join
MATCH (p:Person)-[:WORKS_AT]->(c:Company)
WITH c, collect(p.name) AS employees
RETURN c.name, string_join(employees, ', ') AS team
String Concatenation¶
Use the || operator to concatenate strings:
RETURN 'Hello' || ' ' || 'World' -- 'Hello World'
MATCH (p:Person)
RETURN p.firstName || ' ' || p.lastName AS full_name
toString¶
Convert any value to its string representation:
RETURN toString(42) -- '42'
RETURN toString(3.14) -- '3.14'
RETURN toString(true) -- 'true'
RETURN toString(null) -- null
Pattern Matching¶
GQL provides several string matching operators in WHERE clauses. See Filtering for details.