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How to do SQL-if exists and then select?
if exists (select * from Table where FieldValue=”) then begin select TableID from Table where FieldValue=” end else begin insert into Table (FieldValue) values (”) select TableID from Table where TableID = scope_identity () end. You could also do: if not exists (select * from Table where FieldValue=”) then begin insert into Table
How to select first value in SQL Server?
Select first value if exists, otherwise select default value. Given an instance of SQL Server, imagine there’s a table named Configuration, which has three columns: ID, Name, and Data. There should be no duplicate rows for Name.
How to select the default value in SQL?
There is a more generic approach that takes care of what said by Martin Smith in his comment, but is more verbose (using the hypothesis that the configuration name are unique) The ID of the Default Value is set to NULL to avoid to use a magic number.
Why is the ID of the default value set to null?
The ID of the Default Value is set to NULL to avoid to use a magic number. From the BOL: NULL values are treated as the lowest possible values. IMO a general solution should be used only where a specific one is not possible, and that doesn’t seems the case.
How to select all records from one table that does not exist?
This is the strategy: you create two implicit temporary tables and make a union of them. The first temporary table comes from a selection of all the rows of the first original table the fields of which you wanna control that are NOT present in the second original table.
How to insert tableid into a table in SQL?
IF EXISTS (SELECT * FROM Table WHERE FieldValue=”) THEN SELECT TableID FROM Table WHERE FieldValue=” ELSE INSERT INTO TABLE (FieldValue) VALUES (”) SELECT TableID FROM Table WHERE TableID=SCOPE_IDENTITY () END IF
How to select table a from Table B?
Table A carries status information of a fleet of equipment. Each status record carries with it a start and stop time of that status. Table B carries regularly recorded, timestamped data about the equipment, which I want to extract for the duration of the period indicated in table A. Thanks for contributing an answer to Stack Overflow!
How to avoid duplicates in insert into select?
I want to avoid two INSERT INTO-SELECT statements based on some condition. Of the three options, the LEFT JOIN/IS NULL is less efficient. See this link for more details. Does SQL Server have anything similar? I was facing the same problem recently… Heres what worked for me in MS SQL server 2017… The primary key should be set on ID in table 2…
How to prevent duplicate entries in a range?
If Intersect (Target, EvalRange) Is Nothing Or Target.Cells.Count > 1 Then Exit Sub If IsEmpty (Target) Then Exit Sub ‘If the value entered already exists in the defined range on the current worksheet, throw an ‘error message and undo the entry.
Is there a re-use option for SQL?
Unfortunately, for a variety of reasons (not just legacy) SQL does not have nearly all of the code re-use options and features that most client languages have and some of them (like scalar UDFs) have significant problems.