REPEAT
Description
The REPEAT function is used to repeat a specified string a specified number of times to generate a new string. This function is commonly used for generating padding characters, creating separators, or generating test data.
Syntax
REPEAT(<str>, <count>)
Parameters
| Parameter | Description |
|---|---|
<str> | The source string to repeat. Type: VARCHAR |
<count> | The number of times to repeat, must be a non-negative integer. Type: INT |
Return Value
Returns VARCHAR type, representing the string repeated the specified number of times.
Repeat rules:
- When count is greater than 0, returns the result of str repeated count times
- When count equals 0, returns an empty string
- When count is less than 0, returns an empty string
- If the resulting string is too long, it may be subject to string length limitations
Special cases:
- If any parameter is NULL, returns NULL
- If str is an empty string, returns an empty string regardless of count
- If count is 0, returns an empty string
- If count is negative, returns an empty string
Examples
- Basic character repetition
SELECT REPEAT('a', 3);
+----------------+
| REPEAT('a', 3) |
+----------------+
| aaa |
+----------------+
- Multi-character string repetition
SELECT REPEAT('hello', 2);
+--------------------+
| REPEAT('hello', 2) |
+--------------------+
| hellohello |
+--------------------+
- Zero repetitions
SELECT REPEAT('test', 0);
+-------------------+
| REPEAT('test', 0) |
+-------------------+
| |
+-------------------+
- Negative repetitions
SELECT REPEAT('a', -1);
+-----------------+
| REPEAT('a', -1) |
+-----------------+
| |
+-----------------+
- NULL value handling
SELECT REPEAT(NULL, 3), REPEAT('a', NULL);
+------------------+-------------------+
| REPEAT(NULL, 3) | REPEAT('a', NULL) |
+------------------+-------------------+
| NULL | NULL |
+------------------+-------------------+
- Empty string repetition
SELECT REPEAT('', 5);
+----------------+
| REPEAT('', 5) |
+----------------+
| |
+----------------+
- Special character repetition
SELECT REPEAT('-', 10), REPEAT('*', 5);
+------------------+-----------------+
| REPEAT('-', 10) | REPEAT('*', 5) |
+------------------+-----------------+
| ---------- | ***** |
+------------------+-----------------+
- UTF-8 character repetition
SELECT REPEAT('ṭṛì', 3), REPEAT('ḍḍu', 2);
+-------------------+-------------------+
| REPEAT('ṭṛì', 3) | REPEAT('ḍḍu', 2) |
+-------------------+-------------------+
| ṭṛìṭṛìṭṛì | ḍḍuḍḍu |
+-------------------+-------------------+
- Mixed numbers and symbols
SELECT REPEAT('123', 3), REPEAT('@#', 4);
+-------------------+------------------+
| REPEAT('123', 3) | REPEAT('@#', 4) |
+-------------------+------------------+
| 123123123 | @#@#@#@# |
+-------------------+------------------+
- UTF-8 character repetition
SELECT REPEAT('ṭṛìṭṛì', 3);
+--------------------------------------------------+
| REPEAT('ṭṛìṭṛì', 3) |
+--------------------------------------------------+
| ṭṛìṭṛìṭṛìṭṛìṭṛìṭṛì |
+--------------------------------------------------+
Description
The REPEAT function is used to repeat a string a specified number of times.
Syntax
REPEAT( <str>, <count> )
Parameters
| Parameter | Description |
|---|---|
<str> | The string to be repeated. |
<count> | The number of times to repeat. It must be a non-negative integer. If it is less than 1, an empty string will be returned. |
Return Value
Returns the string repeated the specified number of times. Special cases:
- If any Parameter is NULL, NULL will be returned.
Examples
SELECT repeat("a", 3);
+----------------+
| repeat('a', 3) |
+----------------+
| aaa |
+----------------+
SELECT repeat("a", -1);
+-----------------+
| repeat('a', -1) |
+-----------------+
| |
+-----------------+
