I want to share my way to convert a string to Base64 and back. Let me note that presented method is not the fastest, but it has one important advantage - it works OOB, without CLR functions. We need a test database and a table to use as an example:

Very few people have thought about this performance killer. It is all about report parameter of text type.The initial situationThere was a table with about 45 million rows. Some columns in the table were VARCHAR and should have been filtered. As a result of filtering by 10 different parameters the total number of rows could have been significantly reduced. SQL Server was going for table scan in this case. Also there was a number of indexes defined on the table.