Comment character/characters in postgres / postgresql / psql?

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难免孤独
难免孤独 2020-12-24 10:54

What\'s the character for comments in postgres?

SELECT * FROM my_table     # pound  sign produces a syntax error

Thank you cababunga, the f

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  • 2020-12-24 11:23

    From the official documentation: PostgreSQL Comments.

    A comment is a sequence of characters beginning with double dashes and extending to the end of the line, e.g.:

    -- This is a standard SQL comment
    

    Alternatively, C-style block comments can be used:

    /* multiline comment  * with nesting: /* nested block comment */  */
    

    where the comment begins with /* and extends to the matching occurrence of */. These block comments nest, as specified in the SQL standard but unlike C, so that one can comment out larger blocks of code that might contain existing block comments.

    A comment is removed from the input stream before further syntax analysis and is effectively replaced by whitespace.

    And it has been supported the same way ever since dark ages (version 7.0).

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  • 2020-12-24 11:25

    According to PostgreSQL documentation, there are both the inline and the block style comments.

    The inline style:

    SELECT 23 AS test  -- this is just a test
    

    The block style:

    /* The following is a very
     * non-trivial SQL code */
    SELECT 42 AS result
    
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  • 2020-12-24 11:28

    It's Better to select and press Ctrl+Shift+/ to comment multiline in PostgreSQL pgAdmin4

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  • 2020-12-24 11:44

    It doesn't look like psql supports traditional end-of-line -- comments in its psql-specific "slash commands."

    However, if you're okay with the end-of-line comments being displayed on execution, using \echo seems to be a valid work-around. For example:

    \dt jvcurve_thin.jvcurve_results   \echo my comment #2
    

    The "double slash" separator meta-command looks like another possibility (and without the side effect of echoing). Begin a new command with it and immediately start a -- comment:

    \dt jvcurve_thin.jvcurve_results   \\ -- my comment #2
    

    Finally, switching to the shell and adding a shell comment seems like another possibility:

    \dt jvcurve_thin.jvcurve_results   \! # my comment #2
    
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  • 2020-12-24 11:48

    In SQL comment starts with --.

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