---

{ “title”: “STRLEFT”, “language”: “en”, “description”: “The STRLEFT function returns a specified number of characters from the left side of a string. The length is measured in UTF8 characters.” }

Description

The STRLEFT function returns a specified number of characters from the left side of a string. The length is measured in UTF8 characters.

Alias

LEFT

Syntax

STRLEFT(<str>, <len>)

Parameters

Parameter	Description
<str>	The string to extract from. Type: VARCHAR
<len>	The number of characters to return. Type: INT

Return Value

Returns VARCHAR type, representing the extracted substring.

Special cases:

• Returns NULL if any argument is NULL
• Returns empty string "" if len is less than or equal to 0
• Returns the entire string if len is greater than the string length

Examples

1. Basic left extraction

SELECT STRLEFT('Hello doris', 5), LEFT('Hello doris', 5);

+---------------------------+----------------------+
| STRLEFT('Hello doris', 5) | LEFT('Hello doris', 5) |
+---------------------------+----------------------+
| Hello                     | Hello                |
+---------------------------+----------------------+

2. Different extraction lengths

SELECT STRLEFT('Hello World', 3), STRLEFT('Hello World', 8);

+----------------------------+----------------------------+
| STRLEFT('Hello World', 3)  | STRLEFT('Hello World', 8)  |
+----------------------------+----------------------------+
| Hel                        | Hello Wo                   |
+----------------------------+----------------------------+

3. NULL value handling

SELECT STRLEFT(NULL, 5), STRLEFT('Hello doris', NULL);

+------------------+------------------------------+
| STRLEFT(NULL, 5) | STRLEFT('Hello doris', NULL) |
+------------------+------------------------------+
| NULL             | NULL                         |
+------------------+------------------------------+

4. Empty string and zero length

SELECT STRLEFT('', 5), STRLEFT('Hello World', 0);

+------------------+----------------------------+
| STRLEFT('', 5)   | STRLEFT('Hello World', 0)  |
+------------------+----------------------------+
|                  |                            |
+------------------+----------------------------+

5. Negative length handling

SELECT STRLEFT('Hello doris', -5), STRLEFT('Hello doris', -1);

+-----------------------------+----------------------------+
| STRLEFT('Hello doris', -5)  | STRLEFT('Hello doris', -1) |
+-----------------------------+----------------------------+
|                             |                            |
+-----------------------------+----------------------------+

6. Length exceeds string length

SELECT STRLEFT('ABC', 10), STRLEFT('short', 20);

+--------------------+----------------------+
| STRLEFT('ABC', 10) | STRLEFT('short', 20) |
+--------------------+----------------------+
| ABC                | short                |
+--------------------+----------------------+

7. UTF-8 multi-byte characters

SELECT STRLEFT('ṭṛì ḍḍumai hello', 3), STRLEFT('ṭṛì ḍḍumai hello', 7);

+---------------------------------+----------------------------------+
| STRLEFT('ṭṛì ḍḍumai hello', 3)  | STRLEFT('ṭṛì ḍḍumai hello', 7)  |
+---------------------------------+----------------------------------+
| ṭṛì                             | ṭṛì ḍḍu                          |
+---------------------------------+----------------------------------+

8. Number and ID prefix

SELECT STRLEFT('ID123456789', 5), STRLEFT('USER_987654321', 5);

+----------------------------+------------------------------+
| STRLEFT('ID123456789', 5)  | STRLEFT('USER_987654321', 5) |
+----------------------------+------------------------------+
| ID123                      | USER_                        |
+----------------------------+------------------------------+

Keywords

STRLEFT, LEFT