mysql多表查询案例
@蔺点2549：mysql 多表查询并排序
汪些15338533581…… 1.查询一张表: select * from 表名; 2.查询指定字段:select 字段1,字段2,字段3….from 表名; 3.where条件查询:select 字段1,字段2,字段3 frome 表名 where 条件表达式;例:select * from t_studect where id=1; select * from t_student ...
@蔺点2549：“mysql ”多表联合查询语句怎么写? -
汪些15338533581…… 一使用SELECT子句进行多表查询SELECT 字段名 FROM 表1,表2 … WHERE 表1字段 = 表2字段 AND 其它查询条件SELECT a.id,a.name,a.address,a.date,b.math,b.english,b.chinese FROM tb_demo065_tel AS b,tb_demo065 AS a WHERE a....
@蔺点2549：MySQL多表查询(超过10个相关的表) -
汪些15338533581…… 你可以试试下面这个: select * from table as a inner (join) table_2 as b on (a.ch=b.ch) inner (join) table_3 as c on (c.ch=b.ch) inner (join) table_4 as d on (d.ch =c.ch) inner (join) table_5 as e on (e.ch = d.ch) inner (join) table_6 as f on (f.ch =e.ch) ...
@蔺点2549：MYSQL多表联查 -
汪些15338533581…… 方法一:子查询 select nam,tim from stunt where tim in (select tim from log) limit (0,5)方法一:联合查询(join) select stunt.nam,stunt,tim from stunt as s join log as l on l.tim = s.tim limit (0,5)
@蔺点2549：MySQL 联合多表统计查询 -
汪些15338533581…… SELECT m.user_id, b_total, c_total, d_total FROM a m, (SELECT user_id, COUNT(*) b_total FROM b GROUP BY user_id) n, (SELECT user_id, COUNT(*) c_total FROM c GROUP BY user_id) j, (SELECT user_id, COUNT(*) d_total FROM d GROUP BY user_id) k,WHERE m.user_id = n.user_id AND m.user_id = j.user_id AND m.user_id = k.user_id;
@蔺点2549：mysql 如何在多个表中查数据 -
汪些15338533581…… select a1 ,a2 from table1 where a2='班组长' union all select a1,a2 from table2 where a2='班组长' union all select a1,a2 from table3 where a2='班组长'
@蔺点2549：在mysql中怎么同时查询多个表的数据 -
汪些15338533581…… 你是要干什么呢?要把2个表关联起来查询?select tbl1.mid,tbl1.tim,tbl2.mid,tb2.tim from tbl1,tbl2 where tbl1.mid = tbl2.mid and tbl1.mid = 9 order by tbl1.tim 还是要把2个表的查询结果放到一起?select mid,tim from tbl1 where mid = 9 union select mid,tim from tbl2 where mid = 9 order by tim
@蔺点2549：mysql怎么多表查询两张不同的数据库表呢 -
汪些15338533581…… select * from zz_baojie where sid =381 union select * from zz_demos where sid =423 会报错,原因就像你自己说的,两张表的字段数不同 作为程序员,其实尽量少用select * from ... 因为这种写法在后期维护的时候存在很大的隐患 正确的做法就是 select 后面跟具体的字段名, 虽然这么写比一个星号来的费时费力,但对于程序来说是有百利而无一害的
@蔺点2549：MySQL 如何多表查询 -
汪些15338533581…… 我觉得:1. 表结构不同的话,用你的来方法比较好,速度自快. 写成这样:select count(*) from `知b` where `nid` = '123'; 直接统计出数目道了 2.表结构相同的话: 写成这样select count(*) from `a` where `nid` = '123' UNION ALL select count(*) from `b` where `nid` = '123';
@蔺点2549：mysql多表外键查询的例子 -
汪些15338533581…… 现有两个表table1和table2,id相同,均为主键,也就是外键 SELECT A.*,B.* from table1 as A,table2 as B where A.*=B.* and A.*=* 把*换成你的条件- -#完了
汪些15338533581…… 1.查询一张表: select * from 表名; 2.查询指定字段:select 字段1,字段2,字段3….from 表名; 3.where条件查询:select 字段1,字段2,字段3 frome 表名 where 条件表达式;例:select * from t_studect where id=1; select * from t_student ...
@蔺点2549：“mysql ”多表联合查询语句怎么写? -
汪些15338533581…… 一使用SELECT子句进行多表查询SELECT 字段名 FROM 表1,表2 … WHERE 表1字段 = 表2字段 AND 其它查询条件SELECT a.id,a.name,a.address,a.date,b.math,b.english,b.chinese FROM tb_demo065_tel AS b,tb_demo065 AS a WHERE a....
@蔺点2549：MySQL多表查询(超过10个相关的表) -
汪些15338533581…… 你可以试试下面这个: select * from table as a inner (join) table_2 as b on (a.ch=b.ch) inner (join) table_3 as c on (c.ch=b.ch) inner (join) table_4 as d on (d.ch =c.ch) inner (join) table_5 as e on (e.ch = d.ch) inner (join) table_6 as f on (f.ch =e.ch) ...
@蔺点2549：MYSQL多表联查 -
汪些15338533581…… 方法一:子查询 select nam,tim from stunt where tim in (select tim from log) limit (0,5)方法一:联合查询(join) select stunt.nam,stunt,tim from stunt as s join log as l on l.tim = s.tim limit (0,5)
@蔺点2549：MySQL 联合多表统计查询 -
汪些15338533581…… SELECT m.user_id, b_total, c_total, d_total FROM a m, (SELECT user_id, COUNT(*) b_total FROM b GROUP BY user_id) n, (SELECT user_id, COUNT(*) c_total FROM c GROUP BY user_id) j, (SELECT user_id, COUNT(*) d_total FROM d GROUP BY user_id) k,WHERE m.user_id = n.user_id AND m.user_id = j.user_id AND m.user_id = k.user_id;
@蔺点2549：mysql 如何在多个表中查数据 -
汪些15338533581…… select a1 ,a2 from table1 where a2='班组长' union all select a1,a2 from table2 where a2='班组长' union all select a1,a2 from table3 where a2='班组长'
@蔺点2549：在mysql中怎么同时查询多个表的数据 -
汪些15338533581…… 你是要干什么呢?要把2个表关联起来查询?select tbl1.mid,tbl1.tim,tbl2.mid,tb2.tim from tbl1,tbl2 where tbl1.mid = tbl2.mid and tbl1.mid = 9 order by tbl1.tim 还是要把2个表的查询结果放到一起?select mid,tim from tbl1 where mid = 9 union select mid,tim from tbl2 where mid = 9 order by tim
@蔺点2549：mysql怎么多表查询两张不同的数据库表呢 -
汪些15338533581…… select * from zz_baojie where sid =381 union select * from zz_demos where sid =423 会报错,原因就像你自己说的,两张表的字段数不同 作为程序员,其实尽量少用select * from ... 因为这种写法在后期维护的时候存在很大的隐患 正确的做法就是 select 后面跟具体的字段名, 虽然这么写比一个星号来的费时费力,但对于程序来说是有百利而无一害的
@蔺点2549：MySQL 如何多表查询 -
汪些15338533581…… 我觉得:1. 表结构不同的话,用你的来方法比较好,速度自快. 写成这样:select count(*) from `知b` where `nid` = '123'; 直接统计出数目道了 2.表结构相同的话: 写成这样select count(*) from `a` where `nid` = '123' UNION ALL select count(*) from `b` where `nid` = '123';
@蔺点2549：mysql多表外键查询的例子 -
汪些15338533581…… 现有两个表table1和table2,id相同,均为主键,也就是外键 SELECT A.*,B.* from table1 as A,table2 as B where A.*=B.* and A.*=* 把*换成你的条件- -#完了
