Is null or empty mysql?
I have a column in a table which might contain null or empty values. How do I check if a column is empty or null in the rows present in a table?
asked Dec 12, 2011 at 6:49
3 This will select all rows where
answered Dec 12, 2011 at 6:54
mačekmaček 74.1k36 gold badges164 silver badges196 bronze badges 2
As defined by the SQL-92 Standard, when comparing two strings of differing widths, the narrower value is right-padded with spaces to make it is same width as the wider value. Therefore, all string values that consist entirely of spaces (including zero spaces) will be deemed to be equal e.g.
Therefore, this should work regardless of how many spaces make up the
or more succinctly:
answered Dec 12, 2011 at 12:28
onedaywhenonedaywhen 53.6k12 gold badges96 silver badges135 bronze badges 3
A shorter way to write the condition:
Since answered Jun 30, 2013 at 16:24
AndomarAndomar 227k45 gold badges368 silver badges392 bronze badges 6 Please mind: the best practice it at the end of the answer. You can test whether a column is null or is not null using
In your example you have various permutations of white space. You can strip white space using e.g.
This final query will return rows where If you can avoid it, it's better not to have a function on a column in the WHERE clause as it makes it difficult to use an index. If you simply want to check if a column is null or empty, you may be better off doing this:
See TRIM COALESCE and IS NULL for more info. Also Working with null values from the MySQL docs
answered Dec 12, 2011 at 6:52
Code MagicianCode Magician 22.5k6 gold badges59 silver badges77 bronze badges 2 Another method without WHERE, try this.. Will select both Empty and NULL values
answered Jan 3, 2016 at 17:06
PodTech.ioPodTech.io 4,46834 silver badges24 bronze badges 2 Either
or
answered Jun 7, 2017 at 3:48
This statement is much cleaner and more readable for me:
answered May 30, 2016 at 16:10
AmaynutAmaynut 3,9115 gold badges38 silver badges43 bronze badges try
or
Reference answered Dec 12, 2011 at 6:53
diEchodiEcho 52.6k41 gold badges172 silver badges242 bronze badges I hate messy fields in my databases. If the column might be a blank string or null, I'd rather fix this before doing the select each time, like this:
This keeps the data tidy, as long as you don't specifically need to differentiate between NULL and empty for some reason. answered Dec 3, 2014 at 17:16
1 While checking Every Database doesn't support Below is the matrix just to understand the supported methods by different databases. The TRIM function in SQL is used to remove specified prefix or suffix from a string. The most common pattern being removed is white spaces. This function is called differently in different databases:
How to Check Empty/Null :-
The syntax for these trim functions are:
Above both ways provide same result just use based on your DataBase support. It Just returns the Hoping this will help you :) answered Oct 21, 2016 at 20:58
Vikash PandeyVikash Pandey 5,3036 gold badges39 silver badges42 bronze badges If you want to have NULL values presented last when doing an ORDER BY, try this:
answered Dec 12, 2011 at 6:52
GhostmanGhostman 5,9589 gold badges33 silver badges52 bronze badges 0 You can also do
The inverse being
answered Jun 22, 2017 at 3:18
brenjtbrenjt 15.7k13 gold badges78 silver badges116 bronze badges 2
Paul Roub 36k27 gold badges80 silver badges88 bronze badges answered Feb 12, 2019 at 15:47
3 My two cents. In MySQL you can use the
So you can simplify your query like this:
answered Sep 8, 2021 at 9:54
PiozPioz 5,7353 gold badges45 silver badges60 bronze badges
answered Jan 25, 2019 at 13:15
Hakan IlgarHakan Ilgar 1415 silver badges14 bronze badges 2 In my case, space was entered in
the column during the data import and though it looked like an empty column its length was 1. So first of all I checked the length of the empty looking column using
answered Feb 20, 2019 at 15:46
MR ANDMR AND 3365 silver badges26 bronze badges 1 The below SQL query works fine.
answered Mar 23 at 13:55
try this if the datatype are string and row is null
if the datatype are int or column are 0 then try this
answered Mar 31, 2017 at 3:00
Get rows with NULL, 0, '', ' ', ' '
Get rows without NULL, 0, '', ' ', ' '
answered Sep 23, 2020 at 19:41
ArthurArthur 1172 bronze badges 1
Nathan Tuggy 2,23627 gold badges29 silver badges38 bronze badges answered Jun 7, 2017 at 2:59
2 Is NULL or empty in MySQL?The IS NULL constraint can be used whenever the column is empty and the symbol ( ' ') is used when there is empty value. mysql> SELECT * FROM ColumnValueNullDemo WHERE ColumnName IS NULL OR ColumnName = ' '; After executing the above query, the output obtained is.
Is NULL or empty SQL?NULL is used in SQL to indicate that a value doesn't exist in the database. It's not to be confused with an empty string or a zero value. While NULL indicates the absence of a value, the empty string and zero both represent actual values.
Is NULL 0 or blank?In database terms, however, a null value is a value that doesn't exist: the field does not contain a value of any kind (not even a blank value). By contrast, a blank value is a real value: it just happens to be a string value containing 0 characters.
Is NULL or NULL MySQL?Conceptually, NULL means “a missing unknown value” and it is treated somewhat differently from other values. Because the result of any arithmetic comparison with NULL is also NULL , you cannot obtain any meaningful results from such comparisons. In MySQL, 0 or NULL means false and anything else means true.
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