MAPREDUCE服务 MRS-SELECT查询表数据:使用示例

时间：2024-11-28 01:44:36

MAPREDUCE服务 MRS

使用示例

--查看ClickHouse集群信息
select * from system.clusters;
--显示当前节点设置的宏
select * from system.macros;
--查看数据库容量
select
sum(rows) as "总行数",
formatReadableSize(sum(data_uncompressed_bytes)) as "原始大小",
formatReadableSize(sum(data_compressed_bytes)) as "压缩大小",
round(sum(data_compressed_bytes) / sum(data_uncompressed_bytes) * 100,
0) "压缩率"
from system.parts;
--查询test表容量。where条件根据实际情况添加修改
select
sum(rows) as "总行数",
formatReadableSize(sum(data_uncompressed_bytes)) as "原始大小",
formatReadableSize(sum(data_compressed_bytes)) as "压缩大小",
round(sum(data_compressed_bytes) / sum(data_uncompressed_bytes) * 100,
0) "压缩率"
from system.parts
where table in ('test')
and partition like '2020-11-%'
group by table;

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