Some DBMSs returnNULLs before values, others return values first. I’d like to see more consistency, but in both cases it is just a practical choice that does not contradict any interpretation ofNULL. Oracles implements theORDER BY ... NULLS FIRSTandNULLS LASTsyntax. Outer joins Left, right...
When ANSI_NULLS is on (which you should always set on anyway, since the option to not have it on is going to be removed in the future), any comparison operation where (at least) one of the operands is NULL produces the third logic value - UNKNOWN (as opposed to TRUE and FALSE). U...
CREATE NONCLUSTERED INDEX [IX_Categories] ON [dbo].[be_Categories] ( [CategoryName] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [Secondary] GO You can get m...
What is the purpose of COALESCE in SQL? COALESCE serves to return the first non-NULL value from a set of expressions. It helps manage NULL values efficiently in SQL queries by substituting them with alternate, meaningful values. How does COALESCE differ from ISNULL? Can COALESCE handle ...
COUNT(*) Returns all rows ignoring nulls right? What does COUNT(*) OVER() do? This question came in a practice exam so I didn't have the data to query. I have been using Adventure Works and this site http://www.sqlishard.com/Exercise to practice. If I enter a query like SELECT ...
Finance: The financial industry uses data warehousing in the same way that the banking industry does. The right solution assists the financing industry in analyzing customer expenses, allowing them to develop better strategies for maximizing profits on both ends. Insurance: In the insurance industry,...
I realize the primary key doesn't allow nulls. I just didn't know if there was another purpose for the primary key under the hood of sql server. Sounds as though there isn't. I think we are going to change our processes to create these as primary keys as opposed...
Rule 12: Nonsubversion Rule There should be no way to modify the database structure other than through the multiple row database language (like SQL). Most databases today support administrative tools that allow some direct manipulation of the datastructure. Was this answer useful? Yes Reply...
Our improved SQL statement is: SELECT ProductID, COALESCE(Color + ' ','') + Name FROM Production.Product How does the work? I’ve highlighted some important bits in the statement: If color is the value “Black,” then the COALESCE function will return “Black “ with the training space...
Query Planner to better handle redundant IS [NOT] NULL: When you create a table you can create a column, select the name and type and whether it can allow NULLS or not—and you can put a NOT NULL constraint on the column. When you write a query you might write WHE...