Chapter 5. Reference

This reference section describes in detail each of the SQL commands supported by the PostgreSQL. The commands are given in alphabetical order. Each command is shown using the following conventions:

• The Synopsis shows the command keywords in uppercase. Text you need to replace with your own values is shown in lowercase.

  • Command elements between square brackets "[]" are optional. If there is more than one option to choose from, the options are separated by vertical bars "|". You may select one or none of these optional elements.

  • Command elements between curly braces "{}" are required. You must specify at least one of these elements when you use the command. Input describes both the optional keywords and the text you need to replace.

    Some SQL commands have optional words that make the SQL command more like an English sentence. These words are not described.

• Usage provides examples of command use.

• The Output section gives the output that can be generated by the command, including any error messages.

• The Compatibility section describes how a command relates to the SQL standard.

  Some of the PostgreSQL commands are extensions to the SQL standard. When a command is not in the standard but there are similar commands in other DBMS products, the most commonly used syntax has been adopted.