SQL tips: filter first before join
When JOIN multiple tables, the direct and simple way is to sequentially join one-by-one, e.g. if you have a table with schema as, which record a pair of samples, saying ima & imb are item ids. CREATE TABLE IF NOT...
Black coffee 黑咖啡，我的所爱
Every morning, a cup of black coffee is a must before a working day. I love black coffee, no sugar, no cream. The habit is from 2006, when I attended ICASSP conference in Toulouse, French. In a morning when I...
SQL tips: get exclusive data set
In data science & data engineering, it is often required to extracting exclusive data set from a large-scale table in a business date comparing with a history data, e.g. daily new product incremental, weekly new users, ..... Here two ways...
Singapore corrupt practices bureau
Famous corrupt practices bureau located at the Bukit merah, keeping Singapore clean government
A after- raining morning 雨后清晨
After a night raining, it stops in the morning. Fresh air and wet road. Starting a day with my dog walking along the canal river.一夜的雨，早晨起来还略有小雨，早餐后，雨停了，斑斑点点的蓝天漏出了头。每日早晨的必备工作，遛狗。雨后小蓝天Symmetric world 小二黑雨露滋润，垂涎欲滴Morning, my friends we never see each other. Enjoy your life and work.
Tips: mapjoin in long-tail optimization in SQL
When joining a big table, saying A, (e.g.10M records), with a small table, saying B (e.g. 1000 records), based on some keys, the long-tail issue may popup. For example, if you have 10M product & category name records, A, and...
Bicycle: slow death of planet
The following is from recommend post of my LinkedIn friend community. Very good point. Start Sunday morning with happy laugh. Bicycle is the slow death of the planet."A banker made the economists think this when he said:“A cyclist is a...
Morning vs evening orchard road
乌节路的早晨是安静的，只有零零散散上班族：乌节路的傍晚是人潮汹涌，热闹奢华的。楼宇店铺灯火辉煌，shopping eating dating Morning Friday evening
