Data in relational tables is never guaranteed to be returned in a particular order, so adding an ORDER BY to an INSERT INTO statement is meaningless and, pre-SQL Server 2012, could cause performance issues. If you really need to impose a particular order on rows in the table, use a Row_Number() window clause instead. Read more
If you declare a column alias using equals SQL Prompt will raise a violation of a style rule (ST002). It's best to follow the ANSI-SQL92 standard of assigning aliases using the AS keyword. If the alias is not a standard identifier, delimit it with double quotes. using single quotes has long been deprecated (DEP021). Read more
If you want to use TOP with an expression or subquery, or in INSERT, UPDATE, MERGE, and DELETE statements, then use of brackets is required, so it's a good habit to adopt everywhere. Read more
This article shows how to define SQL code analysis rules using SQL Prompt and them run them automatically from a PowerShell script, displaying the detected code issues in a handy HTML report. Read more
Using TOP in a SELECT statement, without a subsequent ORDER BY clause, is legal in SQL Server, but meaningless because asking for the TOP x rows implies that the data is guaranteed to be in a certain order, and tables have no implicit logical order. You must specify the order. Read more
Phil Factor demonstrates the use of temporary tables and table variables, and offers a few simple rules to decide if a table variable will give better performance than a temp table (ST011), or vice-versa (ST012). Read more
Use of the MONEY and SMALLMONEY datatypes can lead to unintentional loss of precision, due to rounding errors, during calculations. It is generally far better to use the DECIMAL, a.k.a. NUMERIC, type. Read more
SELECT…INTO is a useful shortcut for development work, especially for creating temporary tables. However, it no longer has a clear performance advantage and should be avoided in production code. It is better to use a CREATE TABLE statement, where you can specify constraints and datatypes in advance, making it less likely that inconsistencies will sneak into the data. Read more
How to qualify object names, standardize the use of aliases, and make other instant changes that improve the quality and performance of your SQL code. Read more
Phil Factor explains why you should prefer use of EXISTS over IN, when comparing data sets using a subquery. While there is no longer any significant performance advantage, using NOT EXISTS will avoid unexpected results when the subquery’s source data contains NULL values. Read more
