SQL 查詢(xún)

SQL 查詢(xún)

SQL SELECT

SELECT column1, column2, ... FROM table_name; * 代表全部列名 [推薦] 分別列出查詢(xún)列名

SQL DISTINCT[去重復(fù)]

SELECT DISTINCT column1, column2, ... FROM table_name; [注意]僅返回不同的數(shù)據(jù)行，相同行數(shù)據(jù)只顯示一行

SQL WHERE[帶子句]

SELECT column1, column2, ... FROM table_name WHERE condition; [子句]

= 等于

<> 不等于 [!=]

\> 大于

< 小于

\>= 大于等于

<=小于等于

BETWEEN范圍

LIKE 相似

IN ()內(nèi)容

SQL AND & OR [運(yùn)算符]

SELECT column1, column2, ... FROM table_name WHERE condition1 AND condition2 OR condition3 NOT condition4 ...; [運(yùn)算符]為真 執(zhí)行返回，為假 執(zhí)行跳過(guò)忽略

SQL ORDER BY[按關(guān)鍵字排序]

SELECT column1, column2, ... FROM table_name ORDER BY column1, column2, ... ASC|DESC; [備注] ORDER BY 關(guān)鍵字用于按升序或降序?qū)Y(jié)果集進(jìn)行排序。 ORDER BY 關(guān)鍵字默認(rèn)情況下按升序排序記錄。