#alter table

Learn about SQL Server's ALTER TABLE SWITCH statement and how to troubleshoot errors 4907, 4908, and 4912 in my latest #blog post #Microsoft #SQLServer #MadeiraData

Recently we’ve encountered an interesting use case for a customer. They had a table with partitioning that they needed to be archived (with the help of said partitioning), but the ALTER TABLE SWITCH commands were failing with a peculiar error: Error 4907, ‘ALTER TABLE SWITCH’ statement failed. The table ‘MyDB.dbo.PrtTable1’ has 4 partitions while index ‘IX1’ has 6 partitions. This prompted…

When working with SQL Server, the ALTER TABLE statement is a powerful tool for modifying the structure of a table. One common task is adding columns to an existing table, which can be done using the ALTER TABLE statement. This statement allows you to add one or more columns to a table, providing flexibility and the ability to adapt the table's structure to changing requirements.

To add a column to an existing table, you start by using the ALTER TABLE statement followed by the name of the table you want to modify. Then, you use the ADD keyword, followed by the new column name and its data type. For example:

ALTER TABLE TableName ADD NewColumnName DataType;

You can specify various data types for the new column, such as varchar, int, datetime, and more, depending on your data requirements. Additionally, you can include other constraints, such as NOT NULL, DEFAULT values, or foreign key references, to ensure data integrity.

It's important to note that adding a column to an existing table can impact the performance and storage requirements, especially for large tables. Therefore, it's crucial to consider the implications and thoroughly test any modifications before implementing them in a production environment.

Furthermore, if the table already contains data, adding a new column will result in the new column being added to all existing rows with a default value or NULL. You might need to update the existing data in the new column if necessary.

The SQL ALTER TABLE command is used to add, remove or modify columns in an existing table. You should also use the ALTER TABLE command to add and reduce various constraints to the existing table. ALTER TABLE – ADD Column To add a column in a table, use the following syntax: Syntax ALTER TABLE tablename ADD columnname datatype; Example ALTER TABLE Students ADD City…

Sometimes we may want to rename our table to give it a more appropriate name. For this purpose we may use the ALTER TABLE query to rename the table. Syntax ALTER TABLE old_table_name RENAME TO new_table_name;   Example ALTER TABLE students RENAME TO my_students   After using this query, the “students” table will be changed to a new table name “my_students”.

The new “metadata-only column changes” feature in SQL Server 2016 is useless!

You might have seen this blog post by Paul White: New Metadata-Only Column Changes in SQL Server 2016. It talks about how, when a table is compressed, you can change (i.e. increase) a column’s data type without having to create a new table and migrate the data into it, and without having to refactor all of the underlying data. But, not everything is rainbows and unicorns…

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