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MySQL SELECT only not null values

Is it possible to do a select statement that takes only NOT NULL values?

Right now I am using this:

SELECT * FROM table

And then I have to filter out the null values with a php loop.

Is there a way to do:

SELECT * (that are NOT NULL) FROM table

?

Right now when I select * I get val1,val2,val3,null,val4,val5,null,null etc.... but I just want to get the values that are not null in my result. Is this possible without filtering with a loop?

What do you want to happen if there is a row where some columns have NULL values and other columns have not NULL values?
I would like to only get the values from the columns that are not null, and return only the column values in the row that are not null. Right now I use a loop to filter them out, is it possible to do that without a loop?
@bryan - What is your table structure? Do all columns have the same datatype?
@bryan - So what would your ideal result set look like then? A one column result set containing all the non null values? If not editing your question with example data and desired results would be helpful...
@bryan - It sounds like your table may well have repeating groups across columns? (See the Wiki article for an explanation and a suggested alternative structure if that is the case en.wikipedia.org/wiki/First_normal_form)

M
Martin Smith

You should use IS NOT NULL. (The comparison operators = and <> both give UNKNOWN with NULL on either side of the expression.)

SELECT * 
FROM table 
WHERE YourColumn IS NOT NULL;

Just for completeness I'll mention that in MySQL you can also negate the null safe equality operator but this is not standard SQL.

SELECT *
FROM table 
WHERE NOT (YourColumn <=> NULL);

Edited to reflect comments. It sounds like your table may not be in first normal form in which case changing the structure may make your task easier. A couple of other ways of doing it though...

SELECT val1 AS val
FROM  your_table
WHERE val1 IS NOT NULL
UNION ALL
SELECT val2 
FROM  your_table
WHERE val2 IS NOT NULL
/*And so on for all your columns*/

The disadvantage of the above is that it scans the table multiple times once for each column. That may possibly be avoided by the below but I haven't tested this in MySQL.

SELECT CASE idx
         WHEN 1 THEN val1
         WHEN 2 THEN val2
       END AS val
FROM   your_table
        /*CROSS JOIN*/
       JOIN (SELECT 1 AS idx
                   UNION ALL
                   SELECT 2) t
HAVING val IS NOT NULL  /*Can reference alias in Having in MySQL*/

Thanks a lot.. It helped :)
In the last approach, you used CASE statement, not CASE function. So shouldn't it be END CASE instead of END in the SELECT CASE ... part ?
For not-so-expert people, can you explain the last solution ? Does the idx rom the first SELECT come from the idx in the second SELECT ? What does the CASE statement try to accomplish ? What does the second SELECT actually do ? And you are doing an inner join, not a cross join, right ?
I don't think this answers the question. It sounded like OP wanted to select (I assume one specific) row but exclude all columns from that result that were null - this answer requires you to either specify which columns aren't allowed to be null (which is a different problem entirely) or specify all columns, unsuitable for tables with many columns
(e.g. something along the lines of SELECT * FROM table WHERE * IS NOT NULL AND primary_key="somevalue")
M
Mark Byers

You can filter out rows that contain a NULL value in a specific column:

SELECT col1, col2, ..., coln
FROM yourtable
WHERE somecolumn IS NOT NULL

If you want to filter out rows that contain a null in any column then try this:

SELECT col1, col2, ..., coln
FROM yourtable
WHERE col1 IS NOT NULL
AND col2 IS NOT NULL
-- ...
AND coln IS NOT NULL

Update: Based on your comments, perhaps you want this?

SELECT * FROM
(
    SELECT col1 AS col FROM yourtable
    UNION
    SELECT col2 AS col FROM yourtable
    UNION
    -- ...
    UNION
    SELECT coln AS col FROM yourtable
) T1
WHERE col IS NOT NULL

And I agre with Martin that if you need to do this then you should probably change your database design.


Im not sure if I explained it well enough, but im gonna try a little better. Right now when I select * I get val1,val2,val3,null,val4,val5,null,null etc.... but I just want to get the values that are not null in my result. Is this possible without filtering with a loop?
@bryan - Could you explain what columns * returns? Maybe provide a bit of example data in your question as it is not clear from your comment above whether this is all one column.
Right now, * returns all of my values in the row. i.e. val1,val2,val3,null,val4,val5,null,null. But I want it to only return the column values that are not null. Right now I do it with a loop to filter out the values after it returns the result.
A
Aniket Kulkarni
Select * from your_table 
WHERE col1 and col2 and col3 and col4 and col5 IS NOT NULL;

The only disadvantage of this approach is that you can only compare 5 columns, after that the result will always be false, so I do compare only the fields that can be NULL.


p
porquero

I found this solution:

This query select last not null value for each column.

Example

If you have a table:

id|title|body
1 |t1   |b1
2 |NULL |b2
3 |t3   |NULL

you get:

title|body
t3   |b2

Query

SELECT DISTINCT (

  SELECT title
  FROM test
  WHERE title IS NOT NULL 
  ORDER BY id DESC 
  LIMIT 1
) title, (

  SELECT body
  FROM test
  WHERE body IS NOT NULL 
  ORDER BY id DESC 
  LIMIT 1
) body
FROM test

I hope help you.


GROUP_CONCAT(body) AS body
B
Basant

Following query working for me

when i have set default value of column 'NULL' then

select * from table where column IS NOT NULL

and when i have set default value nothing then

select * from table where column <>''

s
soulshake

I use the \! command within MySQL to grep out NULL values from the shell:

\! mysql -e "SELECT * FROM table WHERE column = 123456\G" | grep -v NULL

It works best with a proper .my.cnf where your database/username/password are specified. That way you just have to surround your select with \! mysql e and | grep -v NULL.


D
Developer

MYSQL IS NOT NULL WITH JOINS AND SELECT, INSERT INTO, DELETE & LOGICAL OPERATOR LIKE OR , NOT

Using IS NOT NULL On Join Conditions

 SELECT * FROM users 
 LEFT JOIN posts ON post.user_id = users.id 
 WHERE user_id IS NOT NULL;

 Using IS NOT NULL With AND Logical Operator

 SELECT * FROM users 
 WHERE email_address IS NOT NULL 
 AND mobile_number IS NOT NULL;

Using IS NOT NULL With OR Logical Operator

 SELECT * FROM users 
 WHERE email_address IS NOT NULL 
 OR mobile_number IS NOT NULL;

S
Sᴀᴍ Onᴇᴌᴀ

Yes use NOT NULL in your query like this below.

SELECT * 
FROM table
WHERE col IS NOT NULL;

S
Syscall
SELECT duration,id FROM `tickets` WHERE duration !=""

P
Pang
SELECT * FROM TABLE_NAME
where COLUMN_NAME <> '';

This is not select which are empty. question is for selecting not null values
' ' and null is different