MySql count() to return 0 if no records found
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I have a set of posts on monthly basis. Now i need an array which contains total records of posts posted in each month. I tried below MySql query, Its working fine, but I was expecting 0(Zero) for months where there is no records. Here its not returning 0.
I read that COUNT() will not return '0', So how do i achieve this?
I tried IFNULL(), and COALESCE() but still getting the same result. Please help with this query. Thank You......
SELECT count(id) as totalRec FROM ('post') WHERE year(date) = '2013' AND monthname(date) IN ('January', 'February', 'March') GROUP BY year(date)-month(date) ORDER BY 'date' ASC
+----------+ | totalRec | +----------+ | 7 | | 9 | +----------+
Expected Result (Where there is no posts for January):
+----------+ | totalRec | +----------+ | 0 | | 7 | | 9 | +----------+
+----+---------------------+ | id | date | +----+---------------------+ | 24 | 2012-12-16 16:29:56 | | 1 | 2013-02-25 14:57:09 | | 2 | 2013-02-25 14:59:37 | | 4 | 2013-02-25 15:12:44 | | 5 | 2013-02-25 15:14:18 | | 7 | 2013-02-26 11:31:31 | | 8 | 2013-02-26 11:31:59 | | 10 | 2013-02-26 11:34:47 | | 14 | 2013-03-04 04:39:02 | | 15 | 2013-03-04 05:44:44 | | 16 | 2013-03-04 05:48:29 | | 19 | 2013-03-07 15:22:34 | | 20 | 2013-03-15 12:24:43 | | 21 | 2013-03-16 16:27:43 | | 22 | 2013-03-16 16:29:28 | | 23 | 2013-03-16 16:29:56 | | 11 | 2013-03-17 11:35:12 | +----+---------------------+
MySql count() to return 0 if no records found, The empty row situation should be taken care of at the code behind not at the database, not only is it separation of concern, but more� If the result set had no posts during that time period, you won't get any results to count, hence why it doesn't show. You would need to either join to another table that has all of the year months or fill in the data programmatically when the results are returned.
Did you try
IFNULL() the right way? Maybe try
IFNULL(Count(id), 0) in a
SELECT clause with join.
return empty row if no record found, The COUNT(DISTINCT expression) returns the number of distinct rows that do not contain NULL values as the result of the expression. The return type of the COUNT() function is BIGINT . The COUNT() function returns 0 if there is no matching row found. Suggest to check for return row from sql query, if zero, create a datatable dynamically with the columns identical to the expected return columns of the sql query ,i.e. id, description, price, then add a row with the data that you decide, i.e. 0, 'no record', 0. Then bind it to the gridview. See example: 1. show-header-and-footer-rows-in-empty-row
COALESCE is what you could use, if you have a table of dates and left joined against it. It goes left to right to return the first non null value.
Your group by does look a little nutty at the minute, I have adjusted it.
SELECT COALESCE(count(id),0) as totalRec FROM ('post') LEFT JOIN dates ON dates.date = post.date WHERE year(date) = '2013' AND monthname(date) IN ('January', 'February', 'March') GROUP BY month(date), year(date) ORDER BY 'date' ASC
Where dates table is..
DATE 2013-01-01 2013-01-02 2013-01-03 etc....
MySQL COUNT - Counting Rows in a Table, As all of your values are null, count(cola) has to return zero. If you want to count the rows that are null, you need count(*) SELECT cola, count(*) AS theCount� Description: FOUND_ROWS () should return 1 after any simple query that does SELECT COUNT (*) with no GROUP BY. That is, the SELECT COUNT (*) returns 1 row, whether the query matched any rows or not. But FOUND_ROWS () returns 0 if the previous query was optimized to a NULL join type because of an impossible where. How to repeat: mysql> SELECT COUNT (*) FROM mysql.user; +----------+ | COUNT (*) | +----------+ | 6 | +----------+ mysql> SELECT FOUND_ROWS (); +--------------+ | FOUND_ROWS () |
If the result set had no posts during that time period, you won't get any results to count, hence why it doesn't show.
You would need to either join to another table that has all of the year months or fill in the data programmatically when the results are returned. I can't think of another way to do this, but perhaps it's possible.
Also, as others have said, separate the group by a comma.
Why does COUNT() aggregate return 0 for 'NULL'?, In your case, there was no entry for 5th street in your users table and that is will give the result of inner join and in addition all non-qualifying records from the When you use COUNT with a column name, it counts NOT NULL values. select Name, coalesce( u.ct,0)ct FROM streets s left join ( select StreetID,count(*)ct from � (select addendum_number+1 from aspa2_magaddendum where contractid=:p1), --> HERE QUERY FAILS WHEN NO VALUE IS RETURNED may be the column against it has notnull constraint, if no rows selected the column will have the null value. as other said u can avoid it by having nvl(<query>,0), also you have make sure all the queries will return only one row. instead i will suggest the following insert
Try Like this::
SELECT count(id) as totalRec IF(id NULL, 0, id) As IdList FROM ('post') WHERE year(date) = '2013' AND monthname(date) IN ('January', 'February', 'March') GROUP BY year(date)-month(date) ORDER BY 'date' ASC
To return 0 instead of null in MySQL USE
SELECT id, IF(age IS NULL, 0, age) FROM tblUser
USE with count() having join of 2 tables
tblA_Id Name ----------------- 1 HSP 2 MANI 3 MEET 4 user 5 jaani
tblB_Id SongName tblA_Id ----------------------------- 1 song1 3 2 song2 3 3 song3 1 4 song4 1 5 song4 5
SELECT tblA.tblA_Id, tblA.Name, tblC.SongCount, IF(tblC.SongCount IS NULL, 0, tblC.SongCount) As noOfSong FROM tblA LEFT JOIN ( SELECT ArtistId,count(*) AS SongCount FROM tblB GROUP BY ArtistId ) AS tblC ON tblA.tblA_Id = NoOfSong.ArtistId
tblA_Id Name SongCount noOfSong ------------------------------------------- 5 jaani 1 1 4 user NULL 0 3 MEET 2 2 2 MANI NULL 0 1 HSP 2 2
How to get a group where the count is zero?, I tried below MySql query, Its working fine, but I was expecting 0(Zero) for months where there is no records. Here its not returning 0. I read that COUNT() will not� The COUNT (DISTINCT expression) returns the number of distinct rows that do not contain NULL values as the result of the expression. The return type of the COUNT () function is BIGINT. The COUNT () function returns 0 if there is no matching row found. MySQL COUNT () function illustration
MySql count() to return 0 if no records found, The MySQL COUNT() function allows us to find out how many records are in a table. We can The COUNT function returns a 0 if there are no rows returned. COUNT () function MySQL COUNT () function returns a count of a number of non-NULL values of a given expression. If it does not find any matching row, it returns 0.
Count Rows in MySQL - Querychat, PDOStatement::rowCount() returns the number of rows affected by the last DELETE, This method returns "0" (zero) with the SQLite driver at all times, and with the Instead, use PDO::query() to issue a SELECT COUNT(*) statement with the For MySQL, it will return 1 if the row is inserted, and 2 if it is updated, but that� Hi, I was wondering if it's possible to have MySQL return the default values for a set of columns in a select query where it finds no rows. For example we have a table like: CREATE TABLE `test` ( `test_id` int(10) unsigned NOT NULL default 0, `name` varchar(30) NOT NULL default 'DefaultName' ) And we do a query:
PDOStatement::rowCount - Manual, COUNT(*) counts the number of rows, so the query to count your animals looks like this: You can use COUNT() if you want to find out how many pets each owner has: Query OK, 0 rows affected (0.00 sec) mysql> SELECT owner, COUNT(*) FROM pet; ERROR 1140 The server is free to select the value from any row: It will return no rows if there are no 'test' rows in table1. It sounds like that is your intent except that you want to return 0 if there are no 'test' rows. I have no way to test it now, but I think something like the following will do that. As an aggregate function, MAX will return NULL if there are no 'test' rows.
- can you give sample records where we can play with?
- Your group by looks incorrect
- @JW웃 I have edited my question with sample data..
- nice one. i was about to do a sql fiddle as well. but you beat me to it - as usual :) +1
- WOW, Thanks a lot. I was trying from past 1 hour to get this result, Finally you saved my time. Thank You so much..
- @JW I added April Month to the select list in your JSfiddle example, so result should be [0,7,9,0] but its showing [0,7,9]. Can you please see to it once? sqlfiddle.com/#!2/e0a6e/15
- This really helped me get something done that is similar:--get count of pots used and next1 use plants go select a.pot, count(b.pot_info) as number from (select pot_info as pot from pots union select next1 from pots)a left join plants b on a.pot=b.pot_info group by a.pot order by a.pot
- Sorry, I missed the date table creation bit, thats important