mysql語句匯總

mysql語句匯總

前段時間和同學接的項目終於完工了，項目主要是做報表，涉及到了很多的sql語句，所以借此總結下。

一、基礎

1.數據庫相關命令

a>.創建數據庫

CREATE DATABASE 數據庫名

b>.創建數據庫並設置默認字符集

CREATE DATABASE 數據庫名 DEFAULT CHARACTER SET utf8;

c>.刪除數據庫

DROP DATABASE 數據庫名

2.數據表相關命令

a>.刪除表

DROP TABLE 表名;

b>.新建表

DROP TABLE IF EXISTS 表名;
CREATE TABLE 表名 (
`id`  INT NOT NULL AUTO_INCREMENT,
`username`  VARCHAR(60) NOT NULL DEFAULT '' COMMENT '登錄名',
`password`  CHAR(32) NOT NULL DEFAULT '' COMMENT '登錄密碼',
 PRIMARY KEY (`id`),   -- 主鍵
 INDEX (`username`)    -- 索引
) ENGINE=INNODB DEFAULT CHARSET=utf8 COMMENT='新建表';

c>.修改表名

ALTER TABLE 表名1 RENAME TO 表名2; 

d>.添加列

ALTER TABLE 表名 ADD COLUMN 列名 列類型（如：VARCHAR(30)); 

e>.刪除列

ALTER TABLE 表名 DROP COLUMN 列名; 

f>.幾條簡單的sql語句

選擇：SELECT * FROM 表名 WHERE 范圍;
插入：INSERT INTO 表名(字段名1,字段名2) VALUES(字段值1,字段值2);
刪除：DELETE FROM 表名 WHERE 范圍;
更新：UPDATE 表名 SET 字段名=字段值 WHERE 范圍;
查找：SELECT * FROM 表名 WHERE 字段名 LIKE ’% 字段值 %’ ;
排序：SELECT * FROM 表名 ORDER BY 字段名1,字段名2 [DESC];
總數：SELECT COUNT AS totalcount FROM 表名;
求和：SELECT SUM(字段值) AS sumvalue FROM 表名;
平均：SELECT AVG(字段名) AS avgvalue FROM 表名;
最大：SELECT MAX(字段名) AS maxvalue FROM 表名;
最小：SELECT MIN(字段名) AS minvalue FROM 表名;

g>.賦予數據庫用戶權限（每個數據庫都創建單獨的用戶）

CREATE USER '項目用戶'@'localhost' IDENTIFIED BY '項目用戶密碼';  
GRANT ALL PRIVILEGES ON 數據庫名稱.* TO 項目用戶@'localhost' ; 

或者

GRANT ALL PRIVILEGES ON 數據庫名稱.* TO 用戶名@'%' IDENTIFIED BY '用戶密碼';(用’%'表示從任何地址連接)

h>.添加主鍵

ALTER TABLE 表名 ADD PRIMARY KEY(列名);

i>.創建索引

CREATE INDEX 字段名 ON 表名;

j>.刪除索引

DROP INDEX 字段名;

k>.創建視圖

CREATE VIEW 視圖名 AS
SELECT 語句;

l>.刪除視圖

DROP VIEW 視圖名;

m>.聯合查詢（這塊有很多內容，我這裡只提出基本的）

結果集列聯合：JOIN ，這裡我常用的是LEFT JOIN ，格式如下：

SELECT a.a, a.b, b.c, b.d FROM a LEFT OUT JOIN b ON a.a = b.c;

結果集行聯合：UNION或者UNION ALL，格式如下（注意列的名稱和個數一定要一致）：

SELECT a.a as col1, a.b as col2 from a
UNION ALL
SELECT b.c as col1, b.d as col2 from b;

n>.分組:GROUP BY 一般與count,sum,max,min,avg聯合使用

SELECT SUM(字段名1) FROM 表名 GROUP BY 字段名2;

o>.前10條記錄

SELECT * FROM 表名 LIMIT 0,9;(mysql沒有top語法，limit一般常用來分頁)

p>.排序（desc降序；asc升序；默認是升序）

SELECT * FROM 表名 ORDER BY 列名 DESC;

二、進階

a>.去重，一般常用 DISTINCT

SELECT DISTINCT * FROM 表名;
SELECT DISTINCT(列名) FROM 表名;

b>.復制表

CREATE TABLE 表名2 AS   
(   
  SELECT * FROM 表名1   
)   
     

c>.查詢分析器:在sql前面加上EXPLAIN或者DESC，查看該語句執行情況

EXPLAIN  SELECT * FROM 表名;

三、貼一下做報表時寫的一些惡心的sql

1.根據查詢條件查詢出符合條件的項目編號

SELECT DISTINCT(xp.Id)
FROM xmgl_finance_plan xfp LEFT JOIN xmgl_project xp ON xfp.proId = xp.Id WHERE 1=1
AND xp.proCategory IN ('ITER973')
AND xp.Id IN(0,1,2);

2.-- 查詢項目計劃表裡對應的所有的預算科目對應的合計金額

SELECT
  t.Pid,
  xsb2.subjectName,
  SUM(t.planTotalAmount)    planTotalAmount,
  SUM(t.planCurrentAmount)    planCurrentAmount,
  SUM(t.total_amount)    total_amount,
  SUM(t.payedMoney)    payedMoney,
  SUM(t.finalPayment)    finalPayment,
  SUM(t.CurYearPayedMoney)    CurYearPayedMoney
FROM (SELECT
        xsb.Id,
        xsb.subjectName,
        xsb.Pid,
        SUM(xfp.planTotalAmount)    planTotalAmount,
        SUM(xfp.planCurrentAmount)    planCurrentAmount,
        SUM(xfp.total_amount)    total_amount,
        SUM(xfp.payedMoney)    payedMoney,
        SUM(xfp.finalPayment)    finalPayment,
        SUM(xfp.CurYearPayedMoney)    CurYearPayedMoney
      FROM xmgl_subject_budget xsb
        LEFT JOIN xmgl_project xp
          ON xsb.type = xp.subjectType
        LEFT JOIN xmgl_finance_plan xfp
          ON xsb.Id = xfp.subjectId
      WHERE xp.Id = 1
      GROUP BY xfp.subjectId,xsb.Id
      ORDER BY xsb.Id) AS t
  LEFT JOIN xmgl_subject_budget xsb2
    ON t.Pid = xsb2.Id
WHERE t.Pid <> 0
GROUP BY t.Pid;

3.-- 查詢各個部門在特定科目下的控制額度及支出信息(優化)

SELECT DISTINCT(xcs1.dept),xsc.subjectName,xcs2.amount,COALESCE(SUM(xfa.amount),0) payedMoney
,xcs2.amount-SUM(xfa.amount) leftAmount
FROM xmgl_control_subject xcs1
LEFT JOIN xmgl_control_subject xcs2 ON xcs1.dept = xcs2.dept AND xcs2.detailId = 3
LEFT JOIN xmgl_subject_control xsc ON xcs2.detailId = xsc.Id
LEFT JOIN xmgl_finance_activity xfa ON xcs2.dept = xfa.department AND xfa.detailId IN('22','23')
GROUP BY xcs1.dept,xcs1.detailId;

4.類似於QQ空間的消息列表

-- 贊了我
SELECT tf.id,1 AS typeId,c.avatar AS avatar, c.name,ct.catalog AS catalog, ct.id AS messageId, ct.content AS trendsContent,NULL AS replyContent, tf.create_time AS createTime,tf.read AS isRead
FROM trends_fork tf LEFT JOIN cust_trends ct ON tf.trends_id = ct.id LEFT JOIN customer c ON c.id = tf.customer_id
WHERE tf.master_id = 1
UNION ALL
-- 給我留言
SELECT cb.id,2 AS typeId,c.avatar AS avatar,c.name, 3 AS catalog,cb.id AS messageId,NULL AS trendsContent,cb.content AS replyContent,cb.create_time AS createTime,cb.read AS isRead
FROM cust_board cb LEFT JOIN customer c ON cb.customer_id = c.id WHERE cb.master_id = 1
UNION ALL
-- 評論我的動態
SELECT  tr.id,3 AS typeId, c.avatar AS avatar, c.name, ct.catalog AS catalog, ct.id AS messageId, ct.content AS trendsContent, tr.content AS replyContent,tr.create_time AS createTime,tr.read AS isRead
FROM trends_reply tr LEFT JOIN cust_trends ct ON tr.trends_id = ct.id LEFT JOIN customer c ON c.id = tr.customer_id
WHERE tr.master_id = 1
UNION ALL
-- 回復了我評論的消息（包括直接回復我的評論、在我的動態下評論別人的回復）
SELECT tra.id,4 AS typeId,c.avatar AS avatar, c.name, ct.catalog AS catalog, tra.trends_id AS messageId,ct.content AS trendsContent, tra.content AS replyContent, tra.create_time AS createTime,tra.read AS isRead
FROM trends_replyat tra LEFT JOIN  trends_reply tr ON tra.reply_id = tr.id LEFT JOIN customer c ON c.id = tra.customer_id LEFT JOIN cust_trends ct ON ct.id = tr.trends_id
WHERE tra.at = 1 OR (tra.master_id = 1 AND tra.customer_id != 1)
UNION ALL
-- 留言板中回復我的消息
SELECT cbr.id,5 AS typeId,c.avatar AS avatar, c.name, 3 AS catalog, cb.id AS messageId,cb.content AS trendsContent,cbr.content AS replyContent, cbr.create_time AS createTime,cbr.read AS isRead
FROM cust_board_reply cbr LEFT JOIN cust_board cb ON cbr.board_id = cb.id LEFT JOIN customer c ON cbr.customer_id = c.id
WHERE (cbr.board_customer_id = 1 AND cbr.customer_id != 1 ) OR (cbr.master_id = 1 AND cbr.customer_id != 1) ORDER BY  createTime DESC
LIMIT 2,10