-- 查看当前 Catalog 和 Database
SHOW CURRENT CATALOG;
SHOW CURRENT DATABASE;

-- 查看所有 Catalog
SHOW CATALOGS;

-- 简单查询
SELECT 1;
SELECT CURRENT_TIMESTAMP AS ts, UUID() AS u;
SELECT CAST('2026-01-01' AS DATE) AS d;

-- 多列查询
SELECT 1 AS id, 'hello' AS name, 3.14 AS pi;

-- 创建临时表（数据生成器）
CREATE TEMPORARY TABLE datagen_source (
  id INT,
  name STRING
) WITH (
  'connector' = 'datagen',
  'rows-per-second' = '1',
  'number-of-rows' = '10'
);

-- 查询临时表
SELECT * FROM datagen_source;

-- 聚合查询
SELECT COUNT(*) AS cnt, AVG(id) AS avg_id FROM datagen_source;

-- 切换到 Paimon Catalog
USE CATALOG my_paimon_catalog;

-- 查看数据库和表
SHOW DATABASES;
USE my_database;
SHOW TABLES;

-- 查询 Paimon 表
SELECT * FROM my_table LIMIT 100;
SELECT COUNT(*) FROM my_table;

-- VALUES 构造数据查询
SELECT * FROM (VALUES (1, 'a'), (2, 'b'), (3, 'c')) AS t(id, name);

-- WHERE 过滤
SELECT x, x*x AS sq FROM (VALUES (1),(2),(3),(4),(5)) AS t(x) WHERE x > 2;

-- GROUP BY 聚合
SELECT grp, COUNT(*) AS cnt, SUM(val) AS total
FROM (VALUES ('a',1), ('a',2), ('b',10), ('b',20)) AS t(grp, val)
GROUP BY grp;

-- 查看当前配置
SET;

-- 查看指定配置
SET 'parallelism.default';

-- 切换执行模式
SET 'execution.runtime-mode' = 'streaming';
SET 'execution.runtime-mode' = 'batch';

-- 设置时区
SET 'table.local-time-zone' = 'Asia/Shanghai';