Manipulating Sampling-Key Expressions Manipulating Sampling-Key Expressions Syntax: ALTER TABLE [ db ]. name [ ON CLUSTER cluster ] MODIFY SAMPLE BY new_expression The c...
Manipulating Sampling-Key Expressions Manipulating Sampling-Key Expressions Syntax: ALTER TABLE [ db ]. name [ ON CLUSTER cluster ] MODIFY SAMPLE BY new_expression The c...
采样子句 SAMPLE K SAMPLE N SAMPLE K OFFSET M 采样子句 该 SAMPLE 子句允许近似于 SELECT 查询处理。 启用数据采样时,不会对所有数据执行查询,而只对特定部分数据(样本)执行查询。 例如,如果您需要计算所有访问的统计信息,只需对所有访问的1/10分数执行查询,然后将结果乘以10即可。 近似...
SAMPLE Clause SAMPLE K SAMPLE N SAMPLE K OFFSET M SAMPLE Clause The SAMPLE clause allows for approximated SELECT query processing. When data sampling is enabled, the query...
sample() function Empty tables Parameters n pos Examples Related articles sample() function The sample() function selects a subset of the records from the input table. ...