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"firstName": "Brett",
"lastName": "McLaughlin",
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"email": "bbbb"
}, {
"firstName": "Elliotte",
"lastName": "Harold",
"email": "cccc"
}],
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"firstName": "Isaac",
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"genre": "sciencefiction"
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"firstName": "Frank",
"lastName": "Peretti",
"genre": "christianfiction"
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"firstName": "Eric",
"lastName": "Clapton",
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"lastName": "Rachmaninoff",
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第1个回答 2020-11-20
第2个回答 2020-12-30
MySQL 从 5.7 开始,增加了新的数据类型:JSON。
JSON 类型的出现,弥补了 MySQL 长期以来相比其他关系型数据库的非标准化特性略势,比如可以用 JSON 来实现类似字典、数组等类型。以及之后大量针对 JSON 类型字串的相关遍历方法与函数。
比如对数组来说,简单的遍历路径为 "$[数组小标]" 或者 "$[*]" 来一次性遍历所有元素。MySQL 8.0 又新增了对于数组元素的范围遍历,比如 "$[m to n]",表示遍历下标为 m 到 n 的元素。
JSON 类型的出现,弥补了 MySQL 长期以来相比其他关系型数据库的非标准化特性略势,比如可以用 JSON 来实现类似字典、数组等类型。以及之后大量针对 JSON 类型字串的相关遍历方法与函数。
比如对数组来说,简单的遍历路径为 "$[数组小标]" 或者 "$[*]" 来一次性遍历所有元素。MySQL 8.0 又新增了对于数组元素的范围遍历,比如 "$[m to n]",表示遍历下标为 m 到 n 的元素。