Rules to Better SQL Databases - Performance

• Identifying the cause of SQL Server performance problems
• Identifying the cause of Azure SQL Database performance problems
• What to do about SQL Server CPU Pressure?
• What to do about SQL Server Memory Pressure?
• What to do about SQL Server IO Pressure?
• Do you keep database tables small?
• Do you only SELECT the columns you require?
• Do you know how to verify SQL indexes are being used?
• Do you avoid implicit data type conversions in SQL queries?
• Do you avoid looping in database queries?
• Do you know that AND is much more efficient than OR in a WHERE clause?
• Do you avoid large database writes?
• Do you avoid avoid using wildcards at the start of a string?
• Do you use JOIN instead of WHERE?
• Do you avoid joining too many tables?
• Do you use TOP for sampling in your queries?