你也可以使用双引号

x = """
this is 
a multiline
string
"""

2.3.3 :012 > x
 => "\nthis is\na multiline\nstring\n"

如果需要删除换行符“\n”，请在每行末尾使用反斜杠“\”

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。

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 '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'

<<是字符串的连接操作符

你也可以使用双引号

x = """
this is 
a multiline
string
"""

2.3.3 :012 > x
 => "\nthis is\na multiline\nstring\n"

如果需要删除换行符“\n”，请在每行末尾使用反斜杠“\”

其他选项:

#multi line string
multiline_string = <<EOM
This is a very long string
that contains interpolation
like #{4 + 5} \n\n
EOM

puts multiline_string

#another option for multiline string
message = <<-EOF
asdfasdfsador #{2+2} this month.
asdfadsfasdfadsfad.
EOF

puts message