ClickHouse/docs/zh/sql-reference/functions/ext-dict-functions.md
2022-08-26 15:07:59 -04:00

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---
slug: /zh/sql-reference/functions/ext-dict-functions
---
# 字典函数 {#zi-dian-han-shu}
有关连接和配置外部词典的信息,请参阅[外部词典](../../sql-reference/functions/ext-dict-functions.md)。
## dictGetUInt8,dictGetUInt16,dictGetUInt32,dictGetUInt64 {#dictgetuint8-dictgetuint16-dictgetuint32-dictgetuint64}
## dictGetInt8,dictGetInt16,dictGetInt32,dictGetInt64 {#dictgetint8-dictgetint16-dictgetint32-dictgetint64}
## dictGetFloat32,dictGetFloat64 {#dictgetfloat32-dictgetfloat64}
## dictGetDate,dictGetDateTime {#dictgetdate-dictgetdatetime}
## dictgetuid {#dictgetuuid}
## dictGetString {#dictgetstring}
`dictGetT('dict_name', 'attr_name', id)`
- 使用id键获取dict_name字典中attr_name属性的值。`dict_name`和`attr_name`是常量字符串。`id`必须是UInt64。
如果字典中没有`id`键,则返回字典描述中指定的默认值。
## dictGetTOrDefault {#ext_dict_functions-dictgettordefault}
`dictGetTOrDefault('dict_name', 'attr_name', id, default)`
与`dictGetT`函数相同,但默认值取自函数的最后一个参数。
## dictIsIn {#dictisin}
`dictIsIn ('dict_name', child_id, ancestor_id)`
- 对于dict_name分层字典查找child_id键是否位于ancestor_id或匹配ancestor_id。返回UInt8。
## dictGetHierarchy {#dictgethierarchy}
`dictGetHierarchy('dict_name', id)`
- 对于dict_name分层字典返回从id开始并沿父元素链继续的字典键数组。返回ArrayUInt64
## dictHas {#dicthas}
`dictHas('dict_name', id)`
- 检查字典是否存在指定的`id`。如果不存在则返回0;如果存在则返回1。
[来源文章](https://clickhouse.com/docs/en/query_language/functions/ext_dict_functions/) <!--hide-->