Reading syntax diagrams

Throughout the Technical Guide, syntax is described using the following structure.

Read the syntax diagrams from the left to the right, from top to bottom, following the path of the line.

Table of Symbols
Symbol Description
symbol01 Indicates the beginning of a statement.
symbol02 Indicates that the statement syntax is continued on the next line.
symbol03 Indicates that a statement is continued from the previous line.
symbol04 Indicates the end of a statement.

Diagrams of syntactical units other than complete statements start with the symbol03 symbol and end with the symbol02 symbol.

  • Required items are displayed on the main path (horizontal line).


  • Optional items are displayed below the main path.


  • If an optional item is displayed above the main path, then that item has no effect on the execution of the statement and is used only for readability.


  • If you can choose from two or more items, then they are displayed vertically, in a stack. If you must choose one of the items, one item of the stack is displayed on the main path.


  • If choosing one of the items is optional, then the entire stack is displayed below the main path.


  • If one of the items is the default, then it is displayed above the main path and the remaining choices will be shown below.


  • An arrow returning to the left, above the main line, indicates an item that can be repeated.


  • If the repeat arrow contains a comma, then you must separate repeated items with a comma.


A repeat arrow above a stack indicates that you can repeat the items in the stack.
  • Keywords are displayed in uppercase (for example, FROM). They must be spelled exactly as shown. Variables are displayed in all lowercase letters (for example, column-name). They represent user-supplied names of values.
  • If punctuation marks, parentheses, arithmetic operators, or other such symbols are shown, you must specify them as part of the syntax.