摘要：
SQL 语句语句语法AND / ORSELECT column_name(s)FROM table_nameWHERE conditionAND|OR conditionALTER TABLE (add column)ALTER TABLE table_nameADD column_name datatypeALTER TABLE (drop column)ALTER TABLE table_nameDROP COLUMN column_nameAS (alias for column)SELECT column_name AS column_aliasFROM table_nameAS (a 阅读全文