STRLEFT

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 usage

SELECT strleft('Hello doris', 5);

+---------------------------+
| strleft('Hello doris', 5) |
+---------------------------+
| Hello                     |
+---------------------------+

2. Handling negative length

SELECT strleft('Hello doris', -5);

+----------------------------+
| strleft('Hello doris', -5) |
+----------------------------+
|                            |
+----------------------------+

3. Handling NULL parameter

SELECT strleft('Hello doris', NULL);

+------------------------------+
| strleft('Hello doris', NULL) |
+------------------------------+
| NULL                         |
+------------------------------+

4. Handling NULL string

SELECT strleft(NULL, 3);

+------------------+
| strleft(NULL, 3) |
+------------------+
| NULL             |
+------------------+