sql - Not equal <> != operator on NULL - Stack Overflow
Oct 9, 2014 · NULL has no value, and so cannot be compared using the scalar value operators. In other words, no value can ever be equal to (or not equal to) NULL because NULL has no …
SQL is null and = null - Stack Overflow
Mar 6, 2012 · In SQL, a comparison between a null value and any other value (including another null) using a comparison operator (eg =, !=, <, etc) will result in a null, which is considered as …
sql - Select rows where column is null - Stack Overflow
May 18, 2011 · How do you write a SELECT statement that only returns rows where the value for a certain column is null?
Why does NULL = NULL evaluate to false in SQL server
Dec 3, 2009 · Also, SQL Server does not give (NULL = NULL) -> FALSE. To quote the documentation for ANSI_NULLS: "When ON is specified, all comparisons to a null value …
sql - IN Clause with NULL or IS NULL - Stack Overflow
Given a null value in id_field, the coalesce function would instead of null return 'unik_null_value', and by adding 'unik_null_value to the IN-list, the query would return posts where id_field is …
SQL: What does NULL as ColumnName imply - Stack Overflow
I understand that AS is used to create an alias. Therefore, it makes sense to have one long name aliased as a shorter one. However, I am seeing a SQL query NULL as ColumnName What …
sql - How to check for null/empty/whitespace values with a single …
Testing on SQL Server 2017, this does work for multiple white spaces without TRIM. It doesn't make sense to me, because according the documentation NULLIF should return NULL only if …
What's the difference between " = null" and " IS NULL"?
The SQL-92 standard requires that an equals (=) or not equal to (<>) comparison against a null value evaluates to FALSE. When SET ANSI_NULLS is ON, a SELECT statement using …
SQL ignore part of WHERE if parameter is null - Stack Overflow
Jul 25, 2013 · The COALESCE function in SQL returns the first non-NULL expression among its arguments. Here for example if the @param1 is equal to null the function will return col1 which …
sql - NULL vs NOT NULL - Stack Overflow
Jun 7, 2012 · In sql database column, empty fields will be set to NULL unless we specify it using NOT NULL. What are the advantages of using one instead of the other? Thanks!