WHILE loops are a fundamental concept in T-SQL programming, allowing us to execute a block of code repeatedly as long as a specified condition is true. Nested WHILE loops take this concept further by placing one WHILE loop inside another, enabling more complex iterations.
This guide will walk you through the basics of nested WHILE loops in SQL Server, complete with simple examples and a demonstration of the BREAK statement.
If you’re getting SQL Server error 1987 that reads something like “Cannot alter nonclustered index ‘UQ_Employees_Email’ on table ‘Employees’ because its clustered index is disabled“, it’s probably because you’re trying to rebuild a nonclustered index when the clustered index for the table is disabled.
To fix this issue, either enable/rebuild the table’s clustered index first, then try again, or enable all indexes at once.
The clustered index will typically be the primary key index (unless you’ve specified another clustered index for the table).
Continue readingIf you’ve got a table that has a UNIQUE constraint, there may come a time where you need to remove it. Whether it’s a permanent thing or temporary, you can easily delete the constraint using the following method.
In SQL Server, a synonym is a database object that provides an alternative name for another database object, such as a table, view, stored procedure, or function. Synonyms act as aliases, allowing us to reference objects using different names without changing the underlying object itself.
The underlying object that the synonym references is typically referred to the base object. Either way, the synonym allows us to reference the base object without actually referring to its name (we refer to the synonym’s name instead).
Continue readingIf you’re getting an error that reads something like “Drop table operation failed on table ‘db.dbo.TableName’ because it is not a supported operation on system-versioned temporal tables” in SQL Server, it’s probably because you’re trying to drop a temporal table that still uses system-versioning.
In SQL Server, if a table is defined as a temporal table, we can’t drop it while it’s using system-versioning.
If you really want to drop the table, turn off system-versioning first, then try again.
Continue readingTemporal tables, introduced in SQL Server 2016, provide a powerful way to track historical data changes. However, there may come a time when you need to remove a temporal table from your database.
This article will guide you through the process of dropping a temporal table in SQL Server.
Continue readingTemporal tables in SQL Server provide a powerful way to track historical data changes. However, when it comes to clearing out data from these tables, the standard TRUNCATE statement doesn’t work the same as it does on normal (non-temporal) tables.
This article will guide you through the process of truncating a temporal table while maintaining its integrity.
Continue readingThe WHILE loop in SQL Server is a control-flow statement that allows us to repeatedly execute a block of code as long as a specified condition is true. It’s useful for iterative tasks and processing data in batches.
While INNER and LEFT JOINs are the workhorses of SQL queries, T-SQL offers several more advanced join techniques that can be invaluable for complex data analysis and manipulation. This article explores some of these powerful join methods and how they can enhance our queries.
Below are the string literal date formats that SQL Server supports for the datetime2 data type. These are the formats that we can provide when setting a datetime2 date from a string literal.
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