clickhouse数据类型转换
时间: 2023-12-06 14:36:50 浏览: 51
ClickHouse兼容了Mysql的数据类型,可以在建表的DDL语句中使用Mysql的数据类型,如BIGINT、TEXT等,ClickHouse会自动将这些类型转换为ClickHouse的数据类型。同时,定义成Mysql的Timestamp,ClickHouse会自动将Timestamp转换为DataTime类型。此外,ClickHouse还支持数组类型Array(T),其中T可以是任何ClickHouse支持的数据类型。
以下是一些ClickHouse数据类型转换的例子:
1. 将Mysql的BIGINT类型转换为ClickHouse的Int64类型
```sql
CREATE TABLE test (
id Int64,
name String
) ENGINE = MergeTree() ORDER BY id;
INSERT INTO test VALUES (9223372036854775807, 'test');
SELECT * FROM test;
```
输出:`(9223372036854775807, 'test')`
2. 将Mysql的TEXT类型转换为ClickHouse的String类型
```sql
CREATE TABLE test (
id Int64,
name String
) ENGINE = MergeTree() ORDER BY id;
INSERT INTO test VALUES (1, 'hello');
SELECT * FROM test;
```
输出:`(1, 'hello')`
3. 将Mysql的Timestamp类型转换为ClickHouse的DateTime类型
```sql
CREATE TABLE test (
id Int64,
time DateTime
) ENGINE = MergeTree() ORDER BY id;
INSERT INTO test VALUES (1, '2022-01-01 00:00:00');
SELECT * FROM test;
```
输出:`(1, 2022-01-01 00:00:00)`