使用 Ruby 拆分 MySQL 查询的行并写入 CSV 文件
Splitting the Rows of a MySQL Query Using Ruby and Writing to a CSV File
使用 Ruby 自动执行来自远程数据库的 MySQL 查询，我希望根据下面找到的 month 查询的值拆分行。
这是为了根据开始日期为所有客户生成 2014 年 6 月份的 week-by-week（星期三到下一个星期二）报告。虽然报告中的其他内容不会发生变化，但行的重复是基于该开始日期（在下面的 case 语句中解释）。
请注意此处 mysql2、watir 和 csv gem 的使用。
简化代码：
#!/usr/local/bin/ruby
require "mysql2"
require "watir"
require "csv"
puts "Initializing Report"
Mysql2::Client.default_query_options.merge!(:as => :array)
mysql = Mysql2::Client.new(:host => "1.2.3.4", :username => "user", :pass => "password", :database => "db")
puts "Successfully accessed db"
month = mysql.query("SELECT DATE_FORMAT(db.table.start, '%m') FROM db.table WHERE db.start.group = 1;")
day = mysql.query("SELECT DATE_FORMAT(db.table.start, '%d') FROM db.table WHERE db.start.group = 1;")
report = mysql.query("SELECT db.table.client, SELECT DATE_FORMAT(db.table.start, '%m/%d/%Y'), SELECT DATE_FORMAT(db.table.end, '%m/%d/%Y') FROM db.table WHERE db.start.group = 1;")
case month
when 5
# code splitting one row into four
when 6
if day <= 4
# code splitting one row into four using weekOf
elsif day >= 11 and day <= 17
# code splitting one row into three using weekOf
elsif day >= 18 and day <= 24
# code splitting one row into two using weekOf
else
# no splitting; only one row using weekOf
end
end
CSV.open("Report.csv", "wb") do |csv|
csv << ["Week of", "Client", "Start Date", "End Date"]
weekOf.zip(report).each {|row| csv << row.flatten}
end
puts "Results can be found in Report.csv"
当前输出（如果我要注释掉 case 语句，删除 CSV header 中的 "Week of", 并且只将 report 查询写入 CSV ):
Client, Start Date, End Date
companyrecordlabel, 05/20/2014, 07/09/2015
beeUrself, 05/27/2014, 02/01/2016
overflowStack, 06/04/2014, 12/11/2015
chapoChaps, 06/11/2014, 01/16/2016
Meds4U, 06/18/2014, NULL
.
.
.
我希望得到以下输出：
Week of, Client, Start Date, End Date
06/04/2014, companyrecordlabel, 05/20/2014, 07/09/2015
06/11/2014, companyrecordlabel, 05/20/2014, 07/09/2015
06/18/2014, companyrecordlabel, 05/20/2014, 07/09/2015
06/25/2014, companyrecordlabel, 05/20/2014, 07/09/2015
06/04/2014, beeUrself, 05/27/2014, 02/01/2016
06/11/2014, beeUrself, 05/27/2014, 02/01/2016
06/18/2014, beeUrself, 05/27/2014, 02/01/2016
06/25/2014, beeUrself, 05/27/2014, 02/01/2016
06/04/2014, overflowStack, 06/04/2014, 12/11/2015
06/11/2014, overflowStack, 06/04/2014, 12/11/2015
06/18/2014, overflowStack, 06/04/2014, 12/11/2015
06/25/2014, overflowStack, 06/04/2014, 12/11/2015
06/11/2014, chapoChaps, 06/11/2014, 01/16/2016
06/18/2014, chapoChaps, 06/11/2014, 01/16/2016
06/25/2014, chapoChaps, 06/11/2014, 01/16/2016
06/18/2014, Meds4U, 06/18/2014, NULL
06/25/2014, Meds4U, 06/18/2014, NULL
.
.
.
为清楚起见："Client" 和 companyrecordlabel 有四行，因为它的 "Start Date" 在五月，而 "Client" Meds4U 只分成两行行，因为它的 "Start Date" 是在 6 月 18 日。
我根据几个假设为以下答案构建了 FULL 代码：
- 没有
DATE_FORMAT(db.table.end, '%m') = 6
- 你希望所有的
列出的公司按其所在的顺序排列（即
db.table.id)
- 查询时间对您来说不是什么大问题
- 您想要但不能或忘记包含一个名为
weekOf 的数组
您在查询中似乎也多次使用 SELECT 一词。即使对于像您提供的示例一样小的查询，您也可能希望将其分开并避免将其全部放在一行中：
month = mysql.query("SELECT DATE_FORMAT(db.table.start, '%m')
FROM db.table
WHERE db.start.group = 1;")
而不是：
month = mysql.query("SELECT DATE_FORMAT(db.table.start, '%m') FROM db.table WHERE db.start.group = 1;")
现在是代码本身：
#!/usr/local/bin/ruby
require "mysql2"
require "watir"
require "csv"
puts "Initializing Report"
Mysql2::Client.default_query_options.merge!(:as => :array)
mysql = Mysql2::Client.new(:host => "1.2.3.4", :username => "user", :pass => "password", :database => "db")
puts "Successfully accessed db"
date = mysql.query("SELECT DATE_FORMAT(db.table.start, '%m'),
DATE_FORMAT(db.table.start, '%d')
FROM db.table
WHERE db.start.group = 1;")
report = mysql.query("SELECT c, s, e FROM (SELECT * FROM (SELECT db.table.id
db.table.client AS c,
DATE_FORMAT(db.table.start, '%m/%d/%Y') AS s,
DATE_FORMAT(db.table.end, '%m/%d/%Y') AS e
FROM db.table
WHERE db.start.group = 1
UNION ALL
SELECT db.table.id
db.table.client AS c,
DATE_FORMAT(db.table.start, '%m/%d/%Y') AS s,
DATE_FORMAT(db.table.end, '%m/%d/%Y') AS e
FROM db.table
WHERE db.start.group = 1
HAVING ((DATE_FORMAT(db.table.start, '%m') = 5) OR (DATE_FORMAT(db.table.start, '%d') <= 4))
UNION ALL
SELECT db.table.id
db.table.client AS c,
DATE_FORMAT(db.table.start, '%m/%d/%Y') AS s,
DATE_FORMAT(db.table.end, '%m/%d/%Y') AS e
FROM db.table
WHERE db.start.group = 1
HAVING ((DATE_FORMAT(db.table.start, '%m') = 5) OR (DATE_FORMAT(db.table.start, '%d') <= 11))
UNION ALL
SELECT db.table.id
db.table.client AS c,
DATE_FORMAT(db.table.start, '%m/%d/%Y') AS s,
DATE_FORMAT(db.table.end, '%m/%d/%Y') AS e
FROM db.table
WHERE db.start.group = 1
HAVING ((DATE_FORMAT(db.table.start, '%m') = 5) OR (DATE_FORMAT(db.table.start, '%d') <= 18))) AS alias
ORDER BY db.table.id) AS alias2;")
weekOf = []
date.each do |mon, day|
if mon === 5
weekOf << "06/04/2014"
weekOf << "06/11/2014"
weekOf << "06/18/2014"
weekOf << "06/25/2014"
elsif mon === 6
if (day.to_i <= 4)
weekOf << "06/04/2014"
weekOf << "06/11/2014"
weekOf << "06/18/2014"
weekOf << "06/25/2014"
elsif ((day.to_i >= 11) && (day.to_i <= 17))
weekOf << "06/11/2014"
weekOf << "06/18/2014"
weekOf << "06/25/2014"
elsif ((day.to_i >= 18) && (day.to_i <= 24))
weekOf << "06/18/2014"
weekOf << "06/25/2014"
else
weekOf << "06/25/2014"
end
else
puts "Error: #{mon} is before May"
end
end
CSV.open("Report.csv", "wb") do |csv|
csv << ["Week of", "Client", "Start Date", "End Date"]
weekOf.zip(report).each {|row| csv << row.flatten}
end
puts "Results can be found in Report.csv"
解释：
我假设查询时间对您来说不是大问题，因为您的示例查询相当小并且不包含 JOIN。如果您发现您的查询变得大于 10 个左右 INNER JOIN（例如 table，每个条目都有数十万个条目），那么这可能不再是您的最佳解决方案。
此解决方案有 两个 部分。
第一个 是使用UNION ALL 从数据库本身复制行。这意味着重复整个查询并在下面添加条件以指定何时发生这种重复。
这就是 HAVING 子句的用武之地。当使用 UNION ALL 时，必须以这种方式使用 HAVING 而不是 WHERE；因为后者会导致 MySQL.
错误
还要记住，作为子查询结果创建的每个 MySQL table 都必须有一个别名：alias 和 alias2。我使用的不是一个而是两个嵌套查询，以便 ORDER BY db.table.id（脱离我的一个假设）然后 select 仅我们下一部分需要的列。
最后，我将两个单独的 month 和 day 组合在一起，而不是将它们变成一个 date：这将在迭代时 return 一个二维数组。
第二个：我创建了您可能想要但忘记包含的 weekOf 数组。
然后我迭代 date 以便将右边的 "06/#{day}/2014" 推入 weekOf 数组。
就是这样！希望对您有所帮助。
使用 Ruby 自动执行来自远程数据库的 MySQL 查询，我希望根据下面找到的 month 查询的值拆分行。
这是为了根据开始日期为所有客户生成 2014 年 6 月份的 week-by-week（星期三到下一个星期二）报告。虽然报告中的其他内容不会发生变化，但行的重复是基于该开始日期（在下面的 case 语句中解释）。
请注意此处 mysql2、watir 和 csv gem 的使用。
简化代码：
#!/usr/local/bin/ruby
require "mysql2"
require "watir"
require "csv"
puts "Initializing Report"
Mysql2::Client.default_query_options.merge!(:as => :array)
mysql = Mysql2::Client.new(:host => "1.2.3.4", :username => "user", :pass => "password", :database => "db")
puts "Successfully accessed db"
month = mysql.query("SELECT DATE_FORMAT(db.table.start, '%m') FROM db.table WHERE db.start.group = 1;")
day = mysql.query("SELECT DATE_FORMAT(db.table.start, '%d') FROM db.table WHERE db.start.group = 1;")
report = mysql.query("SELECT db.table.client, SELECT DATE_FORMAT(db.table.start, '%m/%d/%Y'), SELECT DATE_FORMAT(db.table.end, '%m/%d/%Y') FROM db.table WHERE db.start.group = 1;")
case month
when 5
# code splitting one row into four
when 6
if day <= 4
# code splitting one row into four using weekOf
elsif day >= 11 and day <= 17
# code splitting one row into three using weekOf
elsif day >= 18 and day <= 24
# code splitting one row into two using weekOf
else
# no splitting; only one row using weekOf
end
end
CSV.open("Report.csv", "wb") do |csv|
csv << ["Week of", "Client", "Start Date", "End Date"]
weekOf.zip(report).each {|row| csv << row.flatten}
end
puts "Results can be found in Report.csv"
当前输出（如果我要注释掉 case 语句，删除 CSV header 中的 "Week of", 并且只将 report 查询写入 CSV ):
Client, Start Date, End Date
companyrecordlabel, 05/20/2014, 07/09/2015
beeUrself, 05/27/2014, 02/01/2016
overflowStack, 06/04/2014, 12/11/2015
chapoChaps, 06/11/2014, 01/16/2016
Meds4U, 06/18/2014, NULL
.
.
.
我希望得到以下输出：
Week of, Client, Start Date, End Date
06/04/2014, companyrecordlabel, 05/20/2014, 07/09/2015
06/11/2014, companyrecordlabel, 05/20/2014, 07/09/2015
06/18/2014, companyrecordlabel, 05/20/2014, 07/09/2015
06/25/2014, companyrecordlabel, 05/20/2014, 07/09/2015
06/04/2014, beeUrself, 05/27/2014, 02/01/2016
06/11/2014, beeUrself, 05/27/2014, 02/01/2016
06/18/2014, beeUrself, 05/27/2014, 02/01/2016
06/25/2014, beeUrself, 05/27/2014, 02/01/2016
06/04/2014, overflowStack, 06/04/2014, 12/11/2015
06/11/2014, overflowStack, 06/04/2014, 12/11/2015
06/18/2014, overflowStack, 06/04/2014, 12/11/2015
06/25/2014, overflowStack, 06/04/2014, 12/11/2015
06/11/2014, chapoChaps, 06/11/2014, 01/16/2016
06/18/2014, chapoChaps, 06/11/2014, 01/16/2016
06/25/2014, chapoChaps, 06/11/2014, 01/16/2016
06/18/2014, Meds4U, 06/18/2014, NULL
06/25/2014, Meds4U, 06/18/2014, NULL
.
.
.
为清楚起见："Client" 和 companyrecordlabel 有四行，因为它的 "Start Date" 在五月，而 "Client" Meds4U 只分成两行行，因为它的 "Start Date" 是在 6 月 18 日。
我根据几个假设为以下答案构建了 FULL 代码：
- 没有
DATE_FORMAT(db.table.end, '%m') = 6 - 你希望所有的
列出的公司按其所在的顺序排列（即
db.table.id) - 查询时间对您来说不是什么大问题
- 您想要但不能或忘记包含一个名为
weekOf 的数组
您在查询中似乎也多次使用 SELECT 一词。即使对于像您提供的示例一样小的查询，您也可能希望将其分开并避免将其全部放在一行中：
month = mysql.query("SELECT DATE_FORMAT(db.table.start, '%m')
FROM db.table
WHERE db.start.group = 1;")
而不是：
month = mysql.query("SELECT DATE_FORMAT(db.table.start, '%m') FROM db.table WHERE db.start.group = 1;")
现在是代码本身：
#!/usr/local/bin/ruby
require "mysql2"
require "watir"
require "csv"
puts "Initializing Report"
Mysql2::Client.default_query_options.merge!(:as => :array)
mysql = Mysql2::Client.new(:host => "1.2.3.4", :username => "user", :pass => "password", :database => "db")
puts "Successfully accessed db"
date = mysql.query("SELECT DATE_FORMAT(db.table.start, '%m'),
DATE_FORMAT(db.table.start, '%d')
FROM db.table
WHERE db.start.group = 1;")
report = mysql.query("SELECT c, s, e FROM (SELECT * FROM (SELECT db.table.id
db.table.client AS c,
DATE_FORMAT(db.table.start, '%m/%d/%Y') AS s,
DATE_FORMAT(db.table.end, '%m/%d/%Y') AS e
FROM db.table
WHERE db.start.group = 1
UNION ALL
SELECT db.table.id
db.table.client AS c,
DATE_FORMAT(db.table.start, '%m/%d/%Y') AS s,
DATE_FORMAT(db.table.end, '%m/%d/%Y') AS e
FROM db.table
WHERE db.start.group = 1
HAVING ((DATE_FORMAT(db.table.start, '%m') = 5) OR (DATE_FORMAT(db.table.start, '%d') <= 4))
UNION ALL
SELECT db.table.id
db.table.client AS c,
DATE_FORMAT(db.table.start, '%m/%d/%Y') AS s,
DATE_FORMAT(db.table.end, '%m/%d/%Y') AS e
FROM db.table
WHERE db.start.group = 1
HAVING ((DATE_FORMAT(db.table.start, '%m') = 5) OR (DATE_FORMAT(db.table.start, '%d') <= 11))
UNION ALL
SELECT db.table.id
db.table.client AS c,
DATE_FORMAT(db.table.start, '%m/%d/%Y') AS s,
DATE_FORMAT(db.table.end, '%m/%d/%Y') AS e
FROM db.table
WHERE db.start.group = 1
HAVING ((DATE_FORMAT(db.table.start, '%m') = 5) OR (DATE_FORMAT(db.table.start, '%d') <= 18))) AS alias
ORDER BY db.table.id) AS alias2;")
weekOf = []
date.each do |mon, day|
if mon === 5
weekOf << "06/04/2014"
weekOf << "06/11/2014"
weekOf << "06/18/2014"
weekOf << "06/25/2014"
elsif mon === 6
if (day.to_i <= 4)
weekOf << "06/04/2014"
weekOf << "06/11/2014"
weekOf << "06/18/2014"
weekOf << "06/25/2014"
elsif ((day.to_i >= 11) && (day.to_i <= 17))
weekOf << "06/11/2014"
weekOf << "06/18/2014"
weekOf << "06/25/2014"
elsif ((day.to_i >= 18) && (day.to_i <= 24))
weekOf << "06/18/2014"
weekOf << "06/25/2014"
else
weekOf << "06/25/2014"
end
else
puts "Error: #{mon} is before May"
end
end
CSV.open("Report.csv", "wb") do |csv|
csv << ["Week of", "Client", "Start Date", "End Date"]
weekOf.zip(report).each {|row| csv << row.flatten}
end
puts "Results can be found in Report.csv"
解释：
我假设查询时间对您来说不是大问题，因为您的示例查询相当小并且不包含 JOIN。如果您发现您的查询变得大于 10 个左右 INNER JOIN（例如 table，每个条目都有数十万个条目），那么这可能不再是您的最佳解决方案。
此解决方案有 两个 部分。
第一个 是使用UNION ALL 从数据库本身复制行。这意味着重复整个查询并在下面添加条件以指定何时发生这种重复。
这就是 HAVING 子句的用武之地。当使用 UNION ALL 时，必须以这种方式使用 HAVING 而不是 WHERE；因为后者会导致 MySQL.
还要记住，作为子查询结果创建的每个 MySQL table 都必须有一个别名：alias 和 alias2。我使用的不是一个而是两个嵌套查询，以便 ORDER BY db.table.id（脱离我的一个假设）然后 select 仅我们下一部分需要的列。
最后，我将两个单独的 month 和 day 组合在一起，而不是将它们变成一个 date：这将在迭代时 return 一个二维数组。
第二个：我创建了您可能想要但忘记包含的 weekOf 数组。
然后我迭代 date 以便将右边的 "06/#{day}/2014" 推入 weekOf 数组。
就是这样！希望对您有所帮助。