---

{ “title”: “COUNT_SUBSTRINGS”, “language”: “en”, “description”: “The COUNTSUBSTRINGS function counts the number of occurrences of a specified substring within a string.” }

Description

The COUNT_SUBSTRINGS function counts the number of occurrences of a specified substring within a string. Note: The current implementation continues searching after shifting by the length of the substring when a match is found. For example, when str=‘ccc’ and pattern=‘cc’, the result returned is 1.

Syntax

COUNT_SUBSTRINGS(<str>, <pattern>[, <start_pos>])

Parameters

Parameter	Description
<str>	The string to be searched. Type: STRING
<pattern>	The substring to match. Type: STRING
<start_pos>	Position (1-based) at which the search starts. Type: INT. Optional

Return Value

Returns an INT type, representing the number of times the substring appears in the string.

Special cases:

• If str is NULL, returns NULL
• If pattern is an empty string, returns 0
• If str is an empty string, returns 0
• If start_pos is less than or equal to 0 or exceeds the string length, returns 0

Examples

1. Basic usage

SELECT count_substrings('a1b1c1d', '1');

+----------------------------------+
| count_substrings('a1b1c1d', '1') |
+----------------------------------+
|                                3 |
+----------------------------------+

2. Case with consecutive commas

SELECT count_substrings(',,a,b,c,', ',');

+-----------------------------------+
| count_substrings(',,a,b,c,', ',') |
+-----------------------------------+
|                                 5 |
+-----------------------------------+

3. Case with overlapping substrings

SELECT count_substrings('ccc', 'cc');

+--------------------------------+
| count_substrings('ccc', 'cc')  |
+--------------------------------+
|                              1 |
+--------------------------------+

4. NULL value handling

SELECT count_substrings(NULL, ',');

+-----------------------------+
| count_substrings(NULL, ',') |
+-----------------------------+
|                        NULL |
+-----------------------------+

5. Empty string handling

SELECT count_substrings('a,b,c,abcde', '');

+-------------------------------------+
| count_substrings('a,b,c,abcde', '') |
+-------------------------------------+
|                                   0 |
+-------------------------------------+

6. Using the start position parameter

SELECT count_substrings('ṭṛì ḍḍumai ṭṛì ti ḍḍumannàri', 'ḍḍu', 1), 
       count_substrings('ṭṛì ḍḍumai ṭṛì ti ḍḍumannàri', 'ḍḍu', 6);

+-----------------------------------------------------------------------------------+-----------------------------------------------------------------------------------+
| count_substrings('ṭṛì ḍḍumai ṭṛì ti ḍḍumannàri', 'ḍḍu', 1)                        | count_substrings('ṭṛì ḍḍumai ṭṛì ti ḍḍumannàri', 'ḍḍu', 6)                        |
+-----------------------------------------------------------------------------------+-----------------------------------------------------------------------------------+
|                                                                                 2 |                                                                                 1 |
+-----------------------------------------------------------------------------------+-----------------------------------------------------------------------------------+

7. Start position out of range

SELECT count_substrings('éèêëìíîïðñòó éèêëìíîïðñòó', 'éèê', 0), 
       count_substrings('éèêëìíîïðñòó éèêëìíîïðñòó', 'éèê', 30);

+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------------+
| count_substrings('éèêëìíîïðñòó éèêëìíîïðñòó', 'éèê', 0)                            | count_substrings('éèêëìíîïðñòó éèêëìíîïðñòó', 'éèê', 30)                            |
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------------+
|                                                                                  0 |                                                                                   0 |
+------------------------------------------------------------------------------------+-------------------------------------------------------------------------------------+

7. Start position out of range

SELECT count_substrings('你好，世界！你好，世界！', '世界', 0), 
       count_substrings('你好，世界！你好，世界！', '世界', 30);

+-----------------------------------------------------------------------+------------------------------------------------------------------------+
| count_substrings('你好，世界！你好，世界！', '世界', 0)               | count_substrings('你好，世界！你好，世界！', '世界', 30)               |
+-----------------------------------------------------------------------+------------------------------------------------------------------------+
|                                                                     0 |                                                                      0 |
+-----------------------------------------------------------------------+------------------------------------------------------------------------+