Lexical Issues

Keywords

Though keywords are not case-insensitive, it’s good practice to put them in all caps.

Strings

Strings may be surrounded by either single or double quotes and are always case-sensitive. There are special non-alphanumeric values which can be included in a string if they are escaped. They are: tab, line break, hard return, form feed, single quote and double quote. The syntax for the escaped forms is as follows: \t \b \r \f ', and ".

Identifiers

The identifier, or name, of any object in a query may contain only alphanumeric characters and underscores. Identifiers can’t start with a number and can’t be keywords. It is possible to have identifiers with non-alphanumeric characters if they are enclosed in backticks `. Identifiers which are not enclosed are not case-sensitive. Identifiers which are enclosed are case-sensitive.

Comments

Another useful SQL feature is having the ability to create comments that are stored with saved queries. Comments can be added to any line in a query by putting two dashes at the end of the line (at the beginning of the line if it’s otherwise blank). Anything following the dashes and before a new line is a comment. For example if we wanted to comment the query we ran for the special columns section we could write:

--This query returns all columns for the specified table as well as the two data.world specific columns row_index and row_address.
SELECT product,
       sales_price,
       row_index,
       row_address
  FROM products--any table works
--You must manually list all the columns you would like included.