Question

我想将100个表从MySql转换为MongoDb
所以我认为最简单的方法是将数据导入为JSON
在不使用PHP / ruby / Python的情况下将MySql数据转换为JSON格式的任何通用查询？

SELECT CONCAT(CONCAT('{"CompanyId":', company_id),"}")  AS JSON FROM company;

Answer 1

试试这个：

SET @schema = 'test_db';
SET @table = 'test';

SELECT CONCAT(
  'SELECT CONCAT(TRIM(TRAILING ', QUOTE(','), ' FROM CONCAT(', QUOTE('{'), ',', 
  GROUP_CONCAT(QUOTE('"'), ',', QUOTE(COLUMN_NAME), ',', 
  QUOTE('"'), ',', QUOTE(':'), ',', QUOTE('"'), ',', COLUMN_NAME, ',', 
  QUOTE('"'),',', QUOTE(',')),
  ')), ''}'') FROM ', @table
)
INTO @qry FROM 
  (SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS c
  WHERE TABLE_SCHEMA = @schema AND TABLE_NAME = @table) t;

SELECT @qry;
PREPARE stmt FROM @qry;
EXECUTE stmt;

以上查询以JSON格式生成表数据。使用该查询，您可以准备一个存储过程，将数据库和表名作为输入参数并填充数据。如果要排除表中的某些列，只需修改从INFORMATION_SCHEMA数据库中选择数据的查询，如SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS c WHERE TABLE_SCHEMA = @schema AND TABLE_NAME = @table AND COLUMN_NAME NOT IN (**columns to exclude**)。

Answer 2

我扩展了oardic的答案，创建了一个mysql过程，从表名生成json以及null检查。此键设置为值null而不是空字符串。

create procedure createJSON (IN tabelSchema varchar(255), IN tableName varchar(255), IN whereCondition varchar(255), OUT outJson longtext)
BEGIN
  DROP TEMPORARY TABLE IF EXISTS RowJson;
  SELECT CONCAT(
      'CREATE TEMPORARY TABLE RowJson AS SELECT CONCAT(TRIM(TRAILING ', QUOTE(','), ' FROM CONCAT(', QUOTE('{'), ',',
      GROUP_CONCAT(QUOTE('"'), ',', QUOTE(COLUMN_NAME), ',',
                   QUOTE('"'), ',', QUOTE(':'), ',', 'IF(ISNULL(', COLUMN_NAME, '), "null", CONCAT(',QUOTE('"'),",", COLUMN_NAME, ",", QUOTE('"'),')),',
                   QUOTE(',')),
      ')), ''}'') as json FROM ', tableName, ' WHERE ', whereCondition
  )
  INTO @qry FROM
    (SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS c
    WHERE TABLE_SCHEMA = tabelSchema AND TABLE_NAME = tableName) t;

  PREPARE stmt FROM @qry;
  EXECUTE stmt;

  SELECT json into outJson FROM RowJson;
END;

MySql表变为JSON格式

2 个答案: