Count the number of occurrences of a string in a VARCHAR field?

Question

I have a table like this:

TITLE          |   DESCRIPTION
------------------------------------------------
test1          |   value blah blah value
test2          |   value test
test3          |   test test test
test4          |   valuevaluevaluevaluevalue

I am trying to figure out how to return the number of times a string occurs in each of the DESCRIPTION's.

So, if I want to count the number of times 'value' appears, the sql statement will return this:

TITLE          |   DESCRIPTION                  |   COUNT
------------------------------------------------------------
test1          |   value blah blah value        |   2
test2          |   value test                   |   1
test3          |   test test test               |   0
test4          |   valuevaluevaluevaluevalue    |   5

Is there any way to do this? I do not want to use php at all, just mysql.

Answer 1

This should do the trick:

SELECT 
    title,
    description,    
    ROUND (   
        (
            LENGTH(description)
            - LENGTH( REPLACE ( description, "value", "") ) 
        ) / LENGTH("value")        
    ) AS count    
FROM <table> 

Answer 2

A little bit simpler and more effective variation of @yannis solution:

SELECT 
    title,
    description,    
    CHAR_LENGTH(description) - CHAR_LENGTH( REPLACE ( description, 'value', '1234') ) 
        AS `count`    
FROM <table> 

The difference is that I replace the "value" string with a 1-char shorter string ("1234" in this case). This way you don't need to divide and round to get an integer value.

Generalized version (works for every needle string):

SET @needle = 'value';
SELECT 
    description,    
    CHAR_LENGTH(description) - CHAR_LENGTH(REPLACE(description, @needle, SPACE(LENGTH(@needle)-1))) 
        AS `count`    
FROM <table> 

Answer 3

try this:

 select TITLE,
        (length(DESCRIPTION )-length(replace(DESCRIPTION ,'value','')))/5 as COUNT 
  FROM <table> 

SQL Fiddle Demo

Answer 4

In SQL SERVER, this is the answer

Declare @t table(TITLE VARCHAR(100), DESCRIPTION VARCHAR(100))

INSERT INTO @t SELECT 'test1', 'value blah blah value' 
INSERT INTO @t SELECT 'test2','value test' 
INSERT INTO @t SELECT 'test3','test test test' 
INSERT INTO @t SELECT 'test4','valuevaluevaluevaluevalue' 


SELECT TITLE,DESCRIPTION,Count = (LEN(DESCRIPTION) - LEN(REPLACE(DESCRIPTION, 'value', '')))/LEN('value') 

FROM @t

Result

TITLE   DESCRIPTION               Count
test1   value blah blah value        2
test2   value test                   1
test3   test test test               0
test4   valuevaluevaluevaluevalue    5

I don't have MySQL install, but goggled to find the Equivalent of LEN is LENGTH while REPLACE is same.

So the equivalent query in MySql should be

SELECT TITLE,DESCRIPTION, (LENGTH(DESCRIPTION) - LENGTH(REPLACE(DESCRIPTION, 'value', '')))/LENGTH('value') AS Count
FROM <yourTable>

Please let me know if it worked for you in MySql also.

Answer 5

Here is a function that will do that.

CREATE FUNCTION count_str(haystack TEXT, needle VARCHAR(32))
  RETURNS INTEGER DETERMINISTIC
  BEGIN
    RETURN ROUND((CHAR_LENGTH(haystack) - CHAR_LENGTH(REPLACE(haystack, needle, ""))) / CHAR_LENGTH(needle));
  END;

Answer 6

这是使用空间技术的 mysql 函数（用 mysql 5.0 + 5.5 测试）： CREATE FUNCTION count_str( haystack TEXT, needle VARCHAR(32)) RETURNS INTEGER DETERMINISTIC RETURN LENGTH(haystack) - LENGTH( REPLACE ( haystack, needle, space(char_length(needle)-1)) );

Answer 7

SELECT 
id,
jsondata,    
ROUND (   
    (
        LENGTH(jsondata)
        - LENGTH( REPLACE ( jsondata, "sonal", "") ) 
    ) / LENGTH("sonal")        
)
+
ROUND (   
    (
        LENGTH(jsondata)
        - LENGTH( REPLACE ( jsondata, "khunt", "") ) 
    ) / LENGTH("khunt")        
)
AS count1    FROM test ORDER BY count1 DESC LIMIT 0, 2

Thanks Yannis, your solution worked for me and here I'm sharing same solution for multiple keywords with order and limit.