Manage Data Over Time with SQL Server MERGE Statement
Once data is in a table it needs to be maintained....
2023-02-15
MERGE
Getting started with the SQL MERGE statement
This article is focused on beginners who have already started writing SQL queries and are now diving deep towards more data processing and complex queries in SQL. When we talk about data processing, an important concept that comes to our mind is performing ETL workloads to a data warehouse. ETL is a very complex topic […]
2021-01-26
4,868 reads
SQL Server MERGE statement usage and examples
In this tip we look at how to use MERGE compared to running separate INSERT and UPDATE statements.
2018-09-26
3,483 reads
Using the MERGE Statement to Perform an UPSERT
The term UPSERT has been coined to refer to an operation that inserts rows into a table if they don’t exist, otherwise they are updated. To perform the UPSERT operation Microsoft introduced the MERGE statement. Not only does the MERGE statement support the UPSERT concept, but it also supports deleting records. Greg Larsen discusses how to use the MERGE statement to UPDATE, INSERT and DELETE records from a target table.
2014-12-22
13,060 reads
Create MERGE statements with data!
A script to create MERGE statements with data for specific tables.
2015-09-03 (first published: 2014-05-19)
5,171 reads
Performance of the SQL MERGE vs. INSERT/UPDATE
The SQL MERGE statement offers convenience, safety and elegance, but how does it perform compared to other methods?
2017-02-03 (first published: 2013-10-28)
168,637 reads
A Hazard of Using the SQL Merge Statement
The SQL MERGE statement can make your DML querying more efficient but you need to take care or you may get burned
2013-04-03
24,562 reads
Using the SQL Server MERGE Statement to Process Type 2 Slowly Changing Dimensions
The MERGE statement is powerful and multifunctional, yet it can be hard to master. SOmetimes the MERGE statement that just doesn't do what it's needed to do, like process a Type 2 slowly-changing dimension. Check out this tip to learn more.
2013-03-08
3,847 reads
2013-02-14
2,242 reads
2012-06-20 (first published: 2012-05-30)
8,738 reads
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Fun with JSON II
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Changing Data Types
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Answering Questions On Dropped Columns
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Question of the Day
Fun with JSON II
I have some data in a table:
CREATE TABLE #test_data
(
id INT PRIMARY KEY,
name VARCHAR(100),
birth_date DATE
);
-- Step 2: Insert rows
INSERT INTO #test_data
VALUES
(1, 'Olivia', '2025-01-05'),
(2, 'Emma', '2025-03-02'),
(3, 'Liam', '2025-11-15'),
(4, 'Noah', '2025-12-22');
If I run this query, how many rows are returned?
SELECT t1.[key] AS row,
t2.*
FROM OPENJSON(
(
SELECT t.* FROM #test_data AS t FOR JSON PATH
)
) t1
CROSS APPLY OPENJSON(t1.value) t2; See possible answers