如何使用SQL语句在MongoDB中实现数据压缩和存储优化？

-- 创建统计表
CREATE TABLE IF NOT EXISTS duplicate_stats (
  _id INT PRIMARY KEY,
  count INT
);

-- 压缩重复数据
INSERT INTO duplicate_stats (_id, count)
SELECT field, COUNT(field)
FROM collection
GROUP BY field
HAVING COUNT(field) > 1;

-- 将重复数据替换为标识符
UPDATE collection
SET field = 'duplicate'
WHERE field IN (
  SELECT field
  FROM collection
  GROUP BY field
  HAVING COUNT(field) > 1
);

-- 清除重复数据
DELETE FROM collection
WHERE field = 'duplicate';

-- 创建压缩表
CREATE TABLE IF NOT EXISTS compressed_collection (
  _id INT PRIMARY KEY,
  compressed_data BINARY
);

-- 压缩数据
INSERT INTO compressed_collection (_id, compressed_data)
SELECT _id, COMPRESS(data)
FROM collection;

-- 查询压缩数据
SELECT _id, UNCOMPRESS(compressed_data) AS data
FROM compressed_collection;

-- 创建索引
CREATE INDEX idx_field ON collection (field);

-- 查询数据
SELECT *
FROM collection
WHERE field = 'value';