sql
PostgreSQL bytea与字符串互转
假如name是bytea类型的字段新增时INSERT INTO users (name) VALUES ('zhangsan'::bytea)查询时SELECT CONVERT_FROM(name, 'UTF-8') AS name FROM users
MySQL隐式转换带来的BUG
问题sqlSELECT
IF(o.type = 'A', '优惠', '原价') AS type,
SUM(amount) AS sum
FROM order o
WHERE
GROUP BY IF(o.type = 'A', '优惠', '原价')实际type是tinyint 0-优惠 1-原价这