A database concept used to represent missing, unknown or inapplicable data.

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Null in Varchar datatype

I am using a SQL Server database. If NULL value is inserted to a VARCHAR datatype column, what will be the memory size used for the column?
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117 views

If I assign a NVL constraint to a nullable column will it display an error or it will retrieve the records?

I have a database in which some tables have to be joined to fetch the data. The problem is that in one table the column is nullable (nullable is set to yes or no constraint given for that column) and ...
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1answer
35 views

cant order NULL value properly (mysql)

So I got this view in mysql : CREATE VIEW vote_question_totals AS SELECT question_id , SUM((vote_question_type)='1') question_total_plus , SUM((vote_question_type)='-1') question_total_minus , ...
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1answer
1k views

How to update where subquery value is null in SQL Server

I am attempting to update a column if another value from a subquery is less than a certain value or null: UPDATE Customer SET PriceClassID = 'A' FROM (SELECT custid, SUM(curybaldue) as last_sum FROM ...
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1answer
166 views

Why is replication attempting to distribute NULL values into Identity columns

We are sporadically getting this error: Explicit value must be specified for identity column in our replication environment. I have checked the transaction command that is reporting the error and it ...
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2answers
22 views

MySQL stored procedure returns null

I wrote a simple procedure to modify the whole column to a set of meaningless values. However, when I tried call NewProc('tableName','colName') it returned 1064 - You have an error in your SQL ...
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0answers
29 views

How to best distinguish between “types” of missing data?

I am working on large tables (> 100 fields each) currently organized in flat-files in csv-format. An Oracle DB is to be created to store all the data and allow for several more or less intricate ...
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23 views

Null Dimensions in SSAS [closed]

Several years ago 2008, I create a data warehouse using Business Objects. Business Objects did not process Outer Joins well and used SQL for all of its queries. Therefore, for every dimension I ...
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143 views

How to replace empty, multi-column result with single 'none'

If it is possible to make query in Oracle which will return single column/row with value "none" instead of empty, multi-column result? Otherwise return proper amount of columns with result. This is ...
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1answer
653 views

Populate one table with data from another one on selected cells

I have a problem with filling empty cells in one table with data from another one. I got a table with user emails - some of the fields are empty, some are already containing emails. I gathered the ...
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0answers
25 views

How do I include nulls during comparisons in SQLServer? [duplicate]

So basically in SQLServer a NULL means there is no value and thus can't be compared which returns some unexpected results. For example, the following query doesn't return rows where value IS NULL but ...
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170 views

How to merge rows based on how much data they have?

I am cleaning data and I formed a table something like this: file | product | color | product_id --------------------------------------------- one.csv pipe blue null ...
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136 views

Dealing with null values in non-nullable columns in a NoSQL database

If I have an existing table in a NoSQL database cluster and I want to add a new column that should never return null, how do I handle it in my application code? I can update all exist records and ...
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1answer
452 views

SQL Server's aggregate functions ignore nulls. How do I correct this?

According to MS's knowledgebase, Except for COUNT, aggregate functions ignore null values. Does anyone know how I can get it to work correctly, that is, return a null if it attempts to ...
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2answers
866 views

Is where x = 0 or x is null to be replaced by where isnull(x, 0) = 0 resp. where NVL(x, 0) = 0

Think of x as a column containing null, 0, 1. Only less than 1 % of the rows contain 1. There is no logical difference between 0 and Null. Is it a good idea to insist, that isnull rather than NVL is ...
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1answer
478 views

sql-server optimize query with lots of null checks

I have a query such as: select something from somewhere join stuff on condition join more_stuff on condition where somewhere.sometime is null and somewhere.someone is null and stuff.whatever is null ...
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1answer
254 views

Geography union via cursor returning null

I need to combine multiple geography records into a single entity to store in a spatial data table, but I've learned that the only available function in MSSQL2008R2 that accomplishes this task is ...
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2answers
65 views

How to omit multiple columns where is not null?

I've constructed the below query which satisfies the requirements, except output includes NULL values between all "vendor_address2" columns, which isn't intended. I suspect my error is somewhere ...
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2answers
100 views

How to get the second string in the ORA-02296 error to show something meaningful

Whenever I run the following script*: ALTER TABLE ANIMAL.MONKEY MODIFY TAIL_COUNT NOT NULL; I receive the following error: ORA-02296: cannot enable (ANIMAL.) - null values found I have a ...
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1answer
2k views

How to show NULL results from query?

i'm trying to create a procedure with filters for search. If the parameter is "NULL" the value of parameter will be column value; Here my problem: When my parameter and column value is NULL. I have ...
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2answers
219 views

oracle null value in quotes - yet another newbie question

I have a where clause like "and uc.completion_status in ('[P....]') " here ('[P....]') is the user input from taken a dropdown list in the user interface. and dropdown list consists three options ...
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2answers
2k views

mysql UNIQUE KEY multiple columns with one column as NULL

I understand the way UNIQUE KEY works in Mysql 5.5+, and understand that NULL allows duplicate entries to be created. In following schema and I would finally want that family_relation should have ...
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1answer
7k views

WITH ROLLUP WHERE x IS NULL

I tried to find this question somewhere else on here, and found a couple that were similar to it -- but all the answers seemed pretty convoluted, and I think it was surprising to me because I just ...
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2answers
29 views

Compare possible null values in one query

Question is pretty short and simple: I have following query: SELECT * FROM CTE Now I want to get all rows with only maximum value of some field. SELECT * FROM CTE WHERE NodeId = (SELECT ...
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1answer
70 views

How to prevent #Error values derived from Nulls in an outer join

Suppose I have two tables to outer join Tab1: ID Nam 1 Joe 2 Moe 3 Flo Tab2: ID Val y w 1 stuff 66 33 2 duff 67 44 and one of the resulting columns is derived -- i.e., ...
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1answer
1k views

MySQL is inserting “” as 0 in decimal fields. How to stop that?

The fields are nullable, so they do allow nulls. Why would MySQL convert "" to 0 instead of NULL? Is there a way to force it to be NULL instead?
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2answers
1k views

insert inserted id to another table

Here's the scenario: create table a ( id serial primary key, val text ); create table b ( id serial primary key, a_id integer references a(id) ); create rule a_inserted as on insert to a do ...
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1answer
40 views

multi-column FKs with NULL values

I understand that in PostgreSQL if there is a multi-column FK from table B to table A and one or more of the FK columns in table B are nullable then the FK is still considered as "honored" for the ...
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1answer
38 views

Dealing with co-dependent not null columns

Say I have a table entities (subclassed by people and organizations tables), where each entry requires a primary_email_id. The entities table looks like this: entities ======== id INT AUTO_INCREMENT ...
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1answer
1k views

Return a default value in group by if selected column is null

I am trying to run a group by statement which works fine however, one of the "group" is null. How do I return "Unknown" for that row? For example: 10000 A 9999 B 9990 C 4 etc. First ...
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1answer
861 views

MySQL warnings while loading integer data into table (SOLVED)

For some reason, after loading a large amount of data into the following table (from a single file), all of the values register as 0. CREATE TABLE secondTable ( freq int NULL, w1 int NULL, w2 int ...
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1answer
2k views

Find ID columns with null value in oracle database

I need a way to iterate through all tables in tablespace "T_ECOS" and find all ID with null value in oracle database Any suggestion?
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52 views

Comparisons with NULL values and not using ISNULL function

Hello and thank you in advance. My question is that with ansi-nulls on, how can I do a proper comparison between two fields without using an isnull function (or coalesce)? For example the following ...
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1answer
182 views

Filling not applicable fields with N/A rather than leaving them empty or Null [duplicate]

I have a database of few million records, many of the fields (call them Ec1 to EcN) have either Null or empty string in them. When I looked at them more closely, I found that for many records, several ...
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738 views

Oracle 12c, exclude rows wher two columns are both null

Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit I am trying to select rows with a non-null value in one of two columns. Data is being selected from a view (MY_VIEW) with both ...
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0answers
61 views

MySQL - query join returning zero recs from table with data

I've provided a file that has the table structure and some sample data that I'm working with. I don't understand why I'm getting nulls from a joined table, where there is data. Here's my query ...
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2answers
285 views

Accept null value on parent column in multipart relationship

EDIT: I've come up with one poor solution (below) that requires some denormalization, but does avoid the risks of UDFs in CHECK constraints. I would appreciate your help if you have a better answer. ...
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1answer
702 views

H2 SELECT NULLABLE or other equivalent to check a column has NOT NULL constraint or not

I would like to check if a column has a NOT NULL constraint in order to start an automated upgrade of the table definition. However in H2 the SQL SELECT NULLABLE FROM TABLE_NAME doesn't return me the ...
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4answers
3k views

ISNULL() OR Is NULL in UPDATE statement

I have to run an UPDATE statement on live online database with about 5 lac records. I want to know which statement will run faster: Update Table set REC_ID = isnull(REC_ID,'') Update Table set ...
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1answer
1k views

Totals Column - Blank if Zero or NULL

A report currently computes a "totals" column like so: ,CASE WHEN ISNULL(CLM_BREAKFAST_TYPEA.MealsA, 0) + ISNULL(CLM_BREAKFAST_TYPEB.MealsB, 0) = 0 THEN '' ...
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1answer
329 views

Inserting null value without quotes postgresql

I'm creating a php application which relies on postgresql. Now i have this query: $query= 'INSERT INTO "users" ("name", "username", "email", "phone") VALUES (\''. $name .'\', \''. $username .'\', ...