Do comments slow down SQL?
Can too many comments in a SQL Server 2000 stored procedure slow down that procedure? No, definitely not. Only the active code gets passed to the optimiser, so the comments don’t go anywhere.
What is the use of comment in SQL?
Comments can make your application easier for you to read and maintain. For example, you can include a comment in a statement that describes the purpose of the statement within your application. With the exception of hints, comments within SQL statements do not affect the statement execution.
What is single line comment in SQL?
Single line comments start with — . Any text between — and the end of the line will be ignored (will not be executed).
Does casing matter in SQL?
Answer. No, casing does not matter for the names. This is because SQL is case-insensitive for text values.
Do Caps matter in SQL?
Keywords in SQL are case-insensitive for the most popular DBMSs. The computer doesn’t care whether you write SELECT , select, or sELeCt ; so, in theory, you can write however you like.
Can comments span more than one line?
PL/SQL supports two comment styles: single-line and multi-line. Single-line comments begin with a double hyphen ( – – ) anywhere on a line and extend to the end of the line. Multi-line comments begin with a slash-asterisk ( /* ), end with an asterisk-slash ( */ ), and can span multiple lines.
Can comment also span multiple lines?
Most programming languages have syntax for block comments that span multiple lines of text, like C or Java: /* This is a block comment. It spans multiple lines.
Why is SQL query taking so long?
There are a number of things that may cause a query to take longer time to execute: Inefficient query – Use non-indexed columns while lookup or joining, thus MySQL takes longer time to match the condition. Table lock – The table is locked, by global lock or explicit table lock when the query is trying to access it.
Why is MySQL query taking so long?
How do I add a comment to a transaction in SQL?
Indicates user-provided text. Comments can be inserted on a separate line, nested at the end of a Transact-SQL command line, or within a Transact-SQL statement. The server does not evaluate the comment. Transact-SQL Syntax Conventions.
Do comments affect SQL Server performance?
Paul White is an independent SQL Server consultant specializing in performance tuning, execution plans, and the query optimizer. Every once in a while, a conversation crops up where people are convinced that comments either do or don’t have an impact on performance.
What are the different types of comments in SQL?
1 SQL Comments. Comments are used to explain sections of SQL statements, or to prevent execution of SQL statements. 2 Single Line Comments. Single line comments start with –. Any text between — and the end of the line will be ignored (will not be executed). 3 Multi-line Comments. Multi-line comments start with /* and end with */.
Is there a keyboard shortcut for comments in SQL Server management studio?
For more information about keyboard shortcuts, see SQL Server Management Studio Keyboard Shortcuts. For multiline comments, see Slash Star (Block Comment) (Transact-SQL). The following example uses the — commenting characters. — Choose the AdventureWorks2012 database.