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mysql如何查詢(xún)指定行記錄?
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讓客戶(hù)滿(mǎn)意是我們工作的目標(biāo),不斷超越客戶(hù)的期望值來(lái)自于我們對(duì)這個(gè)行業(yè)的熱愛(ài)。我們立志把好的技術(shù)通過(guò)有效、簡(jiǎn)單的方式提供給客戶(hù),將通過(guò)不懈努力成為客戶(hù)在信息化領(lǐng)域值得信任、有價(jià)值的長(zhǎng)期合作伙伴,公司提供的服務(wù)項(xiàng)目有:主機(jī)域名、虛擬主機(jī)、營(yíng)銷(xiāo)軟件、網(wǎng)站建設(shè)、萬(wàn)寧網(wǎng)站維護(hù)、網(wǎng)站推廣。
2
update table set name='f' where id = 1;
update table set name='f' where id 1 id 5;
mysql怎么指定查詢(xún)一張表的查詢(xún)結(jié)果,如最后5行記錄和最前5行記錄
mysql如何指定查詢(xún)一張表的查詢(xún)結(jié)果,如最后5行記錄和最前5行記錄
mysql如何指定查詢(xún)一張表的查詢(xún)結(jié)果,如最后5行記錄和最前5行記錄
我們以student表為例,里面有三個(gè)字段:id,name,age,其中id為主健,為自增,里面共有10條記錄,如下所示。
mysql select * from student;
+----+------+------+
| id | name | age |
+----+------+------+
| 1 | li | 11 |
| 2 | zh | 12 |
| 3 | chou | 13 |
| 4 | he | 14 |
| 5 | lin | 15 |
| 6 | ll | 16 |
| 7 | chen | 17 |
| 8 | yu | 18 |
| 9 | wu | 19 |
| 10 | xie | 20 |
+----+------+------+
10 rows in set (0.00 sec)
1、查詢(xún)第一行記錄
select * from student limit 1;
+----+------+------+
| id | name | age |
+----+------+------+
| 1 | li | 11 |
+----+------+------+
1 row in set (0.00 sec)
2、查詢(xún)最后一行記錄
select * from student order by id desc limit 1;
+----+------+------+
| id | name | age |
+----+------+------+
| 10 | xie | 20 |
+----+------+------+
1 row in set (0.00 sec)
3、查詢(xún)前n行記錄,如前5行
select * from student limit 5;
select * from student limit 0,5;
select * from student order by id asc limit 5;
上面三條語(yǔ)句的結(jié)果都是一樣的,如下:
+----+------+------+
| id | name | age |
+----+------+------+
| 1 | li | 11 |
| 2 | zh | 12 |
| 3 | chou | 13 |
| 4 | he | 14 |
| 5 | lin | 15 |
+----+------+------+
5 rows in set (0.00 sec)
4、查詢(xún)后n行記錄,如后5條,注意結(jié)果為倒序排序,因?yàn)橛昧薲esc
select * from student order by id desc limit 5;
+----+------+------+
| id | name | age |
+----+------+------+
| 10 | xie | 20 |
| 9 | wu | 19 |
| 8 | yu | 18 |
| 7 | chen | 17 |
| 6 | ll | 16 |
+----+------+------+
5 rows in set (0.00 sec)
5、查詢(xún)第m行到第n行記錄,注意表中的記錄下標(biāo)是從0開(kāi)始的,就像數(shù)組一樣
select * from student limit m,n; 返回m+1到m+n行記錄,m代表開(kāi)始的下標(biāo),n代表查找的結(jié)果數(shù),將返回n行結(jié)果
select * from student limit 2,8; 返回3到10行記錄
+----+------+------+
| id | name | age |
+----+------+------+
| 3 | chou | 13 |
| 4 | he | 14 |
| 5 | lin | 15 |
| 6 | ll | 16 |
| 7 | chen | 17 |
| 8 | yu | 18 |
| 9 | wu | 19 |
| 10 | xie | 20 |
+----+------+------+
8 rows in set (0.00 sec)
select * from student limit 3,1; 返回第4行
+----+------+------+
| id | name | age |
+----+------+------+
| 4 | he | 14 |
+----+------+------+
1 row in set (0.00 sec)
6、查詢(xún)一條記錄($id)的下一條記錄
select * from student where id$id order by id asc limit 1;
如$id=4時(shí)將返回第5條記錄
select * from student where id4 order by id asc limit 1;
+----+------+------+
| id | name | age |
+----+------+------+
| 5 | lin | 15 |
+----+------+------+
1 row in set (0.00 sec)
7、查詢(xún)一條記錄($id)的上一條記錄
select * from student where id$id order by id desc limit 1;
如$id=4時(shí)將返回第3條記錄
select * from student where id4 order by id desc limit 1;
+----+------+------+
| id | name | age |
+----+------+------+
| 3 | chou | 13 |
+----+------+------+
1 row in set (0.00 sec)
mysql行數(shù)限定問(wèn)題
使用sql語(yǔ)句最后加上limit 參數(shù)1,參數(shù)2 一個(gè)參數(shù)是顯示幾行,2個(gè)參數(shù)是從參數(shù)1開(kāi)始顯示,顯示參數(shù)2行
mysql 怎么指定查詢(xún)多少條數(shù)據(jù)
1、創(chuàng)建測(cè)試表,
create table test_limit(id int ,value varchar(100));
2、插入測(cè)試數(shù)據(jù),共6條記錄;
insert into test_limit values (1,'v1');
insert into test_limit values (2,'v2');
insert into test_limit values (3,'v3');
insert into test_limit values (4,'v4');
insert into test_limit values (5,'v5');
insert into test_limit values (6,'v6');
3、查詢(xún)表中全量數(shù)據(jù),可以發(fā)現(xiàn)共6條數(shù)據(jù),select * from test_limit t;
4、編寫(xiě)語(yǔ)句,指定查詢(xún)3條數(shù)據(jù);
select * from test_limit limit 3;
mysql可以指定插入到第幾行嗎
mysql可以指定插入到第幾行。方法是:
1、取消主鍵‘Match_R'的自動(dòng)增加。
2、更改‘Match_R'的值,以便留出插入新數(shù)據(jù)的空間。
3、插入完整的要插入的數(shù)據(jù)。
4、恢復(fù)主鍵‘Match_R'的自動(dòng)增加。
怎樣mysql批量修改字段內(nèi)容的指定行數(shù)
表中數(shù)據(jù)沒(méi)有的行的概念哦,數(shù)據(jù)庫(kù)表里面的數(shù)據(jù),哪個(gè)在前、在后,用戶(hù)是不應(yīng)該關(guān)心的,我們只是在取出數(shù)據(jù)的時(shí)候指定一定規(guī)則進(jìn)行排序,它在數(shù)據(jù)庫(kù)里面究竟是如何排序,我們是不必要、不需要知道和控制的。
補(bǔ)充:
只能通過(guò)某字段等于多少這樣的條件,無(wú)法控制數(shù)據(jù)庫(kù)中第幾條數(shù)據(jù)。一般的修改語(yǔ)句是:
UPDATE 表名 SET options=1 WHERE id BETWEEN 5 AND 20
文章題目:mysql怎么指定行數(shù),mysql怎么獲取行號(hào)
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