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Sql server if statement12/18/2022 ![]() She primarily focuses on the database domain, helping clients build short and long term multi-channel campaigns to drive leads for their sales pipeline. Nupur Dave is a social media enthusiast and an independent consultant. If you need help with any SQL Server Performance Tuning Issues, please feel free to reach out at is also a CrossFit Level 1 Trainer (CF-L1) and CrossFit Level 2 Trainer (CF-L2). ![]() Pinal is an experienced and dedicated professional with a deep commitment to flawless customer service. To freely share his knowledge and help others build their expertise, Pinal has also written more than 5,500 database tech articles on his blog at. Pinal has authored 13 SQL Server database books and 40 Pluralsight courses. He holds a Masters of Science degree and numerous database certifications. Pinal Dave is an SQL Server Performance Tuning Expert and independent consultant with over 17 years of hands-on experience. Let me know if you use any other script which is handy and easy to use. IF EXISTSĪll of the above script give us exactly the same answer. Here is another alternative to the above script with information_schema, which will pretty much work for SQL Server and many other RDBMS as well. PRINT 'Column doesn''t Exists' Option 3: Using Information_Schema IF EXISTS(SELECT 1 FROM sys.columnsĪND Object_ID = Object_ID(N'Person.Address')) However, I prefer to use the option 1 most of the time. Here is another alternate script for the same. It is very common for DBA to use above script when they want to add a new column with the script to any table. Based on those logical evaluations, you can generate various values as part of the returned data set. Well, that is the answer of this question. SQL Server has a unique capability of allowing you to execute real-time programmatic logic on the values within your query. This is what enables you to avoid the use of a SQL Server CURSOR. IF COL_LENGTH('Person.Address', 'AddressID') IS NOT NULL In MySQL, the ITERATE statement is used when you are want a loop body to execute again. I am using the following script for AdventureWorks database. Here is a very simple answer for the question. Always writing the else clause is just good programming, since it documents what's actually happening and give you location in case you would to replace that implicit null with an explicit value.Question: How to check if a column exists in SQL Server table?Īnswer: A fantastic question honestly. how to insert new record in my table if not existssql server 2005. Yes, but you want to tell people that there is a default "ELSE NULL" implicit when it is left off. multiple Insert query for existing row in sql. Sum(CASE WHEN > The ELSE argument is optional. Yet another usage would be good to share. Nice collection of scenarios and use of Case statements. I do always keep the original case as comment for readability :-) Try this on a table selecting a few miljon rows NULLIF and ISNULL are set based, and not RBAR ( row by agonizing row ) and by this a lot more performant. MaritalStatusDesc = ISNULL(NULLIF(ISNULL(NULLIF(,'S'), 'Single'),), 'Married' ) MaritalStatusDesc = CASE WHEN = 'S' THEN 'Single' ELSE 'Married' END The CASE solution however is much more readable and thus easier to maintain. The second query is a little bit slower, but this might just be noise. Note: There is an another IF statement, which differs from the IF() function described in MySQL procedure chapter. ![]() Scan count 1, logical reads 26633, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.ĬPU time = 719 ms, elapsed time = 8456 ms.ĬPU time = 1109 ms, elapsed time = 9230 ms.Īs you can see, logical reads are exactly the same. The results (CASE is first, isnull(nullif()) second): The execution plans are almost exact the same, and both get 50% of the cost. I've blown up the Employee table to a little more than a million rows, so I could test performance between the two statements. However, I've never understood the notion that CASE would be RBAR and thus inherently slow. ISNULL(NULLIF(ISNULL(NULLIF(CONVERT(VARCHAR(50),),'S'), 'Single'),), 'Married' ) Your expression currently doesn't work, because MaritalStatus is only one character long, so all other columns are converted to this data type, which leads to incorrect results (all results are M).
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