有什么办法能让这看起来好一点吗?

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'

比如,有没有办法暗示串联?


当前回答

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。

其他回答

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}
    }

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

有时值得删除新的行字符\n,如:

conn.exec <<-eos.squish
 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

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。