运算符是保留字或主要用于SQL WHERE子句的字符，用于执行操作，例如比较和算术运算. DocumentDB SQL还支持各种标量表达式.最常用的是二进制和一元表达式.
目前支持以下SQL运算符，可以在查询中使用.
以下是DocumentDB SQL语法中可用的所有比较运算符的列表.
| S.No. | 运营商&说明 |
|---|---|
| 1 | = 检查两个操作数的值是否相等.如果是，则条件成立. |
| 2 | ！= 检查两个操作数的值是否相等.如果值不相等则条件成立. |
| 3 | <> 检查两个操作数的值是否相等.如果值不相等则条件成立. |
| 4 | > 检查左操作数的值是否大于右操作数的值.如果是，则条件成立. |
| 5 | < 检查左操作数的值是否小于右操作数的值.如果是，则条件成立. |
| 6 | > = 检查左操作数的值是否大于或等于右操作数的值.如果是，则条件成立. |
| 7 | < = 检查左操作数的值是否小于或等于右操作数的值.如果是，则条件成立. |
以下是DocumentDB SQL语法中可用的所有逻辑运算符的列表.
| S.No. | 运算符&说明 |
|---|---|
| 1 | AND AND运算符允许在SQL语句的WHERE子句中存在多个条件. |
| 2 | BETWEEN BETWEEN运算符用于搜索值给定最小值和最大值时，它们在一组值内. |
| 3 | IN IN运算符用于将值与已指定的文字值列表进行比较. |
| 4 | 或 OR运算符用于组合SQL语句的WHERE子句中的多个条件. |
| 5 | NOT NOT运算符会反转使用它的逻辑运算符的含义.例如，NOT EXISTS，NOT BETWEEN，NOT IN等.这是一个否定运算符. |
以下是DocumentDB SQL语法中可用的所有算术运算符的列表.
| S.No. | 运算符&说明 |
|---|---|
| 1 | + 加法 : 在运算符的任一侧添加值. |
| 2 | - 减法 : 从左手操作数中减去右手操作数. |
| 3 | * 乘法 : 将运算符两侧的值相乘. |
| 4 | / 分部 : 将左手操作数除以右手操作数. |
| 5 | ％ 模数 : 将左手操作数除以右手操作数并返回余数. |
我们将考虑该示例中的相同文档也是如此.以下是 AndersenFamily 文件.
{
"id": "AndersenFamily",
"lastName": "Andersen",
"parents": [
{ "firstName": "Thomas", "relationship": "father" },
{ "firstName": "Mary Kay", "relationship": "mother" }
],
"children": [
{
"firstName": "Henriette Thaulow",
"gender": "female",
"grade": 5,
"pets": [ { "givenName": "Fluffy", "type": "Rabbit" } ]
}
],
"location": { "state": "WA", "county": "King", "city": "Seattle" },
"isRegistered": true
}以下是 SmithFamily 文件.
{
"id": "SmithFamily",
"parents": [
{ "familyName": "Smith", "givenName": "James" },
{ "familyName": "Curtis", "givenName": "Helen" }
],
"children": [
{
"givenName": "Michelle",
"gender": "female",
"grade": 1
},
{
"givenName": "John",
"gender": "male",
"grade": 7,
"pets": [
{ "givenName": "Tweetie", "type": "Bird" }
]
}
],
"location": {
"state": "NY",
"county": "Queens",
"city": "Forest Hills"
},
"isRegistered": true
}以下是 WakefieldFamily 文件.
{
"id": "WakefieldFamily",
"parents": [
{ "familyName": "Wakefield", "givenName": "Robin" },
{ "familyName": "Miller", "givenName": "Ben" }
],
"children": [
{
"familyName": "Merriam",
"givenName": "Jesse",
"gender": "female",
"grade": 6,
"pets": [
{ "givenName": "Charlie Brown", "type": "Dog" },
{ "givenName": "Tiger", "type": "Cat" },
{ "givenName": "Princess", "type": "Cat" }
]
},
{
"familyName": "Miller",
"givenName": "Lisa",
"gender": "female",
"grade": 3,
"pets": [
{ "givenName": "Jake", "type": "Snake" }
]
}
],
"location": { "state": "NY", "county": "Manhattan", "city": "NY" },
"isRegistered": false
}让我们看一个在WHERE子句中使用比较运算符的简单示例.
在此查询中，在WHERE子句中指定了(WHERE f.id ="WakefieldFamily")条件，它将检索id等于WakefieldFamily的文档.
SELECT * FROM f WHERE f.id = "WakefieldFamily"
执行上述查询时，它将返回WakefieldFamily的完整JSON文档，如以下输出所示.
[
{
"id": "WakefieldFamily",
"parents": [
{
"familyName": "Wakefield",
"givenName": "Robin"
},
{
"familyName": "Miller",
"givenName": "Ben"
}
],
"children": [
{
"familyName": "Merriam",
"givenName": "Jesse",
"gender": "female",
"grade": 6,
"pets": [
{
"givenName": "Charlie Brown",
"type": "Dog"
},
{
"givenName": "Tiger",
"type": "Cat"
},
{
"givenName": "Princess",
"type": "Cat"
}
]
},
{
"familyName": "Miller",
"givenName": "Lisa",
"gender": "female",
"grade": 3,
"pets": [
{
"givenName": "Jake",
"type": "Snake"
}
]
}
],
"location": {
"state": "NY",
"county": "Manhattan",
"city": "NY"
},
"isRegistered": false,
"_rid": "Ic8LAJFujgECAAAAAAAAAA==",
"_ts": 1450541623,
"_self": "dbs/Ic8LAA==/colls/Ic8LAJFujgE=/docs/Ic8LAJFujgECAAAAAAAAAA==/",
"_etag": "00000500-0000-0000-0000-567582370000",
"_attachments": "attachments/"
}
]让我们看看另一个例子，其中查询将检索等级大于5的子数据.
SELECT * FROM Families.children[0] c WHERE (c.grade > 5)
执行上述查询时，它将检索输出中显示的以下子文档.
[
{
"familyName": "Merriam",
"givenName": "Jesse",
"gender": "female",
"grade": 6,
"pets": [
{
"givenName": "Charlie Brown",
"type": "Dog"
},
{
"givenName": "Tiger",
"type": "Cat"
},
{
"givenName": "Princess",
"type": "Cat"
}
]
}
]
