Tag: t-sql

Estimate Data Compression Savings in SQL Server

Posted on by Ian

SQL Server has a system stored procedure called sp_estimate_data_compression_savings, which allows you to check an object’s size and its estimated size with various levels of compression.

If the object is already compressed, you can use this procedure to estimate its size when recompressed.

Objects can be compressed by using row, page, columnstore or columnstore archive compression.

Compression can be evaluated for whole tables or parts of tables. This includes heaps, clustered indexes, nonclustered indexes, columnstore indexes, indexed views, and table and index partitions.

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SQL Server Error 110: There are fewer columns in the INSERT statement than values specified in the VALUES clause.

Posted on by Ian

Error message 110 is a commonly encountered error in SQL Server when inserting data into a table. The full error looks like this:

Msg 110, Level 15, State 1, Line 1
There are fewer columns in the INSERT statement than values specified in the VALUES clause. The number of values in the VALUES clause must match the number of columns specified in the INSERT statement.

This happens when you specify less columns in the INSERT statement than the number of values that you’re trying to insert with the VALUES clause.

This will occur if you accidentally omit one or more columns from the INSERT statement.

You’d get a similar (but technically different) error if you tried to do the opposite – specify more columns in the INSERT statement than you try to insert.

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How to Execute a Trigger Only When a Specific Column is Updated (SQL Server)

Posted on by Ian

In SQL Server, you can create DML triggers that execute code only when a specific column is updated.

The trigger still fires, but you can test whether or not a specific column was updated, and then run code only if that column was updated.

You can do this by using the UPDATE() function inside your trigger. This function accepts the column name as its argument. It returns a boolean.

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Send Email from a Trigger in SQL Server (T-SQL)

Posted on by Ian

If you find yourself needing to send an email automatically upon certain events occurring in SQL Server, you can do this via a trigger.

For example, you could automatically send an email when somebody deletes or updates a record from a table, etc.

To do this, you need to create a trigger that includes code for sending the email upon the required event.

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Create an “Instead Of” Trigger in SQL Server

Posted on by Ian

When you create a trigger in SQL Server, you have the option of firing it in conjunction with the triggering statement (i.e. the SQL statement that fired the trigger), or firing it instead of that statement.

To fire the trigger instead of the triggering statement, use INSTEAD OF argument.

This is in contrast to using the FOR or AFTER arguments. When you use those arguments, the trigger fires only when all operations specified in the triggering SQL statement have launched successfully.

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Create a Partitioned Table in SQL Server (T-SQL)

Posted on by Ian

SQL Server supports partitioned tables and indexes. When a partitioned table or index is partitioned, its data is divided into units that can be spread across more than one filegroup.

Therefore, to create a partitioned table in SQL Server, you first need to create the filegroup/s that will hold each partition. You also need to create a partition function and a partition scheme.

So it goes like this:

  1. Create filegroup/s
  2. Create a partition function
  3. Create a partition scheme
  4. Create the partitioned table

Below is an example of using these steps to create a table with four partitions.

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