在ruby 2.0中，你现在可以只使用%

例如:

    SQL = %{
      SELECT user, name
      FROM users
      WHERE users.id = #{var}
      LIMIT #{var2}
    }

conn.exec [
  "select attr1, attr2, attr3, ...",
  "from table1, table2, table3, ...",
  "where ..."
].join(' ')

这个建议的优点在于，自动缩进器可以适当地缩进文档和长字符串的每个部分。但这是以效率为代价的。

像你一样，我也在寻找一个不包括换行符的解决方案。(虽然它们在SQL中可能是安全的，但在我的情况下不安全，我有一个大的文本块要处理)

这可以说是同样丑陋，但你可以在heredoc中反斜杠转义换行符，以从结果字符串中省略它们:

conn.exec <<~END_OF_INPUT
    select attr1, attr2, attr3, attr4, attr5, attr6, attr7 \
    from table1, table2, table3, etc, etc, etc, etc, etc, \
    where etc etc etc etc etc etc etc etc etc etc etc etc etc
  END_OF_INPUT

请注意，如果没有插值(即<<~'END_OF_INPUT')，就不能执行此操作，所以要小心。#{expressions}将在这里求值，而在原始代码中不会求值。答:出于这个原因，威尔逊的回答可能更好。

是的，如果你不介意额外的换行被插入:

 conn.exec 'select attr1, attr2, attr3, attr4, attr5, attr6, attr7
            from table1, table2, table3, etc, etc, etc, etc, etc,
            where etc etc etc etc etc etc etc etc etc etc etc etc etc'

你也可以使用heredoc:

conn.exec <<-eos
   select attr1, attr2, attr3, attr4, attr5, attr6, attr7
   from table1, table2, table3, etc, etc, etc, etc, etc,
   where etc etc etc etc etc etc etc etc etc etc etc etc etc
eos

这个答案中有一些部分帮助我得到了我需要的东西(简单的多行连接，没有额外的空格)，但由于没有实际的答案，我在这里编译它们:

str = 'this is a multi-line string'\
  ' using implicit concatenation'\
  ' to prevent spare \n\'s'

=> "this is a multi-line string using implicit concatenation to eliminate spare
\\n's"

作为奖励，这里有一个使用有趣的HEREDOC语法的版本(通过这个链接):

p <<END_SQL.gsub(/\s+/, " ").strip
SELECT * FROM     users
         ORDER BY users.id DESC
END_SQL
# >> "SELECT * FROM users ORDER BY users.id DESC"

The latter would mostly be for situations that required more flexibility in the processing. I personally don't like it, it puts the processing in a weird place w.r.t. the string (i.e., in front of it, but using instance methods that usually come afterward), but it's there. Note that if you are indenting the last END_SQL identifier (which is common, since this is probably inside a function or module), you will need to use the hyphenated syntax (that is, p <<-END_SQL instead of p <<END_SQL). Otherwise, the indenting whitespace causes the identifier to be interpreted as a continuation of the string.

这并没有节省太多的输入，但对我来说，它看起来比使用+号更好。

此外(我在几年后的编辑中说过)，如果您使用Ruby 2.3+，操作符<<~也可用，它从最终字符串中删除额外的缩进。在这种情况下，您应该能够删除.gsub调用(尽管这可能取决于开始缩进和最终需求)。

编辑:再加一个:

p %{
SELECT * FROM     users
         ORDER BY users.id DESC
}.gsub(/\s+/, " ").strip
# >> "SELECT * FROM users ORDER BY users.id DESC"

conn.exec = <<eos
  select attr1, attr2, attr3, attr4, attr5, attr6, attr7
  from table1, table2, table3, etc, etc, etc, etc, etc,
  where etc etc etc etc etc etc etc etc etc etc etc etc etc
eos