SELECT device_token FROM users WHERE device_token IS NOT NULL AND device_token != '';
SELECT DISTINCT ON device_token FROM users;
ALTER TABLE <Table名稱> ALTER COLUMN <column名稱> SET DEFAULT <預設值>;
// 先在 SQL 輸入以下,安裝插件
create extension cube;
create extension earthdistance;
// 搜尋範例
select (point(-0.1277,51.5073) <@> point(-74.006,40.7144)) as distance;
select (
point(
(select latlng from user_account where first_name = 'Manel')
)
<@>
point(
(select latlng from user_account where first_name = 'Ben')
)
) as distance
DISTINCT ON 只有 postgres 有, MySQL 要使用 group by,另外 postgres 的 group by 不能單獨選擇特定對象,必須要包含在 select 裡面
SELECT *
FROM (
SELECT DISTINCT ON (address_id) *
FROM purchases
WHERE product_id = 1
) p
ORDER BY purchased_at DESC;
SELECT *
FROM (
SELECT DISTINCT ON (customer_name) *
FROM orders
ORDER BY customer_name, create_time DESC
) p
ORDER BY create_time DESC;