How to Fix “Conversion failed when converting the value to data type” in SQL Server

SQL Server error Msg 245, Level 16 tells us that there was a problem when trying to convert a value to a specific data type.

You’ll get this error if you try to insert the wrong data type into a column.

To fix this issue, make sure the data type of the value you’re trying to insert, matches the column’s type.

Continue reading

3 Ways to Return the Number of Rows in Each Partition in SQL Server (T-SQL)

If you’ve previously created a partitioned table in SQL Server, and you now want to know how many rows are being stored in each partition, here are three queries you can use.

In particular, you can:

  • Query the sys.dm_db_partition_stats view
  • Query the sys.partitions view
  • Use the $PARTITION function in a query

Below are examples of all three.

Continue reading

Find Out if a Partition is Compressed in SQL Server (T-SQL)

In SQL Server, you can query the sys.partitions system catalog view to find out whether or not a partition has been compressed.

In particular, the data_compression column tells you whether it’s compressed or not. The data_compression_desc column tells you what type of compression it uses. If it isn’t compressed, it returns NONE.

Continue reading

How to Fix “The select list for the INSERT statement contains fewer items than the insert list”

SQL Server error 120 occurs when you don’t specify enough columns in your INSERT list when using a SELECT list for the values to insert.

To be more specific, it happens when you use a SELECT list in your INSERT statement, but the SELECT list doesn’t return as many columns as you’re specifying with the INSERT.

This is easy to fix. Simply make sure the number of columns match between your INSERT and SELECT list.

Continue reading

Return All Rows From a Specific Partition in SQL Server (T-SQL)

When you create a partitioned table in SQL Server, you specify which values go into each partition.

This is done when you create the partition function. When you create the partition function, you specify boundary values, which determine which values go into each partition.

Once you’ve created your partitioned table, and you’ve inserted data, you can run a normal SELECT statement to return data, just as you would with a non-partitioned table (actually, even non-partitioned tables have one partition).

But did you know that you can also specify which partition you want data from?

You can do this with the help of the $PARTITION system function in your WHERE clause.

Continue reading

How to Fix “ALTER TABLE SWITCH statement failed”

If you’re getting error 4939 while trying to switch a partition in SQL Server, it’s probably because you’re trying to switch to a partition that uses a different filegroup.

One of the requirements of switching partitions is that both the source table or partition, and the target table or partition, must be located in the same filegroup.

Continue reading