$regex 运算符用于通过正则表达式进行模式匹配，尤其适用于查询字符串字段以寻找符合特定模式的匹配项。 常见用例包括搜索字段包含子字符串、以特定前缀开头或匹配复杂模式的文档。
语法
{ "field": { $regex: /pattern/, $options: '<options>' } }
参数
| 参数 | DESCRIPTION |
|---|---|
field |
要查询的文档中的字段 |
/pattern/ |
要匹配的正则表达式模式 |
options |
用于修改正则表达式行为的可选标志。 常见选项包括 i，用于不区分大小写的匹配，m 用于多行匹配，等等。 |
例子
请查看 StoreData 数据库中 stores 集合的这个示例文档。
{
"_id": "0fcc0bf0-ed18-4ab8-b558-9848e18058f4",
"name": "First Up Consultants | Beverage Shop - Satterfieldmouth",
"location": {
"lat": -89.2384,
"lon": -46.4012
},
"staff": {
"totalStaff": {
"fullTime": 8,
"partTime": 20
}
},
"sales": {
"totalSales": 75670,
"salesByCategory": [
{
"categoryName": "Wine Accessories",
"totalSales": 34440
},
{
"categoryName": "Bitters",
"totalSales": 39496
},
{
"categoryName": "Rum",
"totalSales": 1734
}
]
},
"promotionEvents": [
{
"eventName": "Unbeatable Bargain Bash",
"promotionalDates": {
"startDate": {
"Year": 2024,
"Month": 6,
"Day": 23
},
"endDate": {
"Year": 2024,
"Month": 7,
"Day": 2
}
},
"discounts": [
{
"categoryName": "Whiskey",
"discountPercentage": 7
},
{
"categoryName": "Bitters",
"discountPercentage": 15
},
{
"categoryName": "Brandy",
"discountPercentage": 8
},
{
"categoryName": "Sports Drinks",
"discountPercentage": 22
},
{
"categoryName": "Vodka",
"discountPercentage": 19
}
]
},
{
"eventName": "Steal of a Deal Days",
"promotionalDates": {
"startDate": {
"Year": 2024,
"Month": 9,
"Day": 21
},
"endDate": {
"Year": 2024,
"Month": 9,
"Day": 29
}
},
"discounts": [
{
"categoryName": "Organic Wine",
"discountPercentage": 19
},
{
"categoryName": "White Wine",
"discountPercentage": 20
},
{
"categoryName": "Sparkling Wine",
"discountPercentage": 19
},
{
"categoryName": "Whiskey",
"discountPercentage": 17
},
{
"categoryName": "Vodka",
"discountPercentage": 23
}
]
}
]
}
示例 1 - 查找促销活动名称包含子字符串“Days”的所有商店
db.stores.find({"promotionEvents.eventName": {"$regex": /Days/}}, {"name": 1}, {"limit": 3})
这会返回以下结果：
[
{
"_id": "40d6f4d7-50cd-4929-9a07-0a7a133c2e74",
"name": "Proseware, Inc. | Home Entertainment Hub - East Linwoodbury"
},
{
"_id": "f2a8c190-28e4-4e14-9d8b-0256e53dca66",
"name": "Fabrikam, Inc. | Car Accessory Outlet - West Adele"
},
{
"_id": "65300639-9bf0-460c-ae1f-891b2ff479b1",
"name": "Wide World Importers | Fitness Equipment Emporium - Reillyborough"
}
]
示例 2 - 执行不区分大小写的正则表达式模式匹配
查找具有促销事件的所有商店，其中名称包含不区分大小写的子字符串“days”
db.stores.find({"promotionEvents.eventName": {"$regex": /bash/i}})
这会返回以下结果：
[
{
"_id": "40d6f4d7-50cd-4929-9a07-0a7a133c2e74",
"name": "Proseware, Inc. | Home Entertainment Hub - East Linwoodbury"
},
{
"_id": "438db151-04b8-4422-aa97-acf94bc69cfc",
"name": "Fourth Coffee | Turntable Boutique - Tromptown"
},
{
"_id": "c5041337-bd61-4efa-bc7a-02799a2ce82c",
"name": "Wide World Importers | Headphone Corner - McGlynnview"
}
]