① sql 條件只選擇一個
如果是 SQL Server 或 Access：
select top 1 ...
如果是 MySql：
select ... limit 1
② 求一SQL選擇語句
是要分別取6的前四條，7的前四條么？什麼資料庫？以下是sql server 05及以上版本取前2寫法
declare @t table (ID varchar(10), CX varchar(10), CY varchar(10), Npts varchar(10), Pts varchar(10), Age varchar(10))
insert into @t
SELECT '959', '3016', '1430', '36', '23', '6' union all
SELECT '960', '3023', '1422', '24', '14', '6' union all
SELECT '950', '3013', '1419', '59', '37', '8' union all
SELECT '962', '3026', '1419', '24', '14', '6' union all
SELECT '1181', '3037', '1443', '109', '84', '7' union all
SELECT '949', '3010', '1423', '76', '52', '7' union all
SELECT '950', '3013', '1419', '59', '37', '7'
SELECT id,cx,cy,npts,pts,age from (
SELECT id,cx,cy,npts,pts,age,row_number() over (partition by age order by pts) as o
from @t
where age in ('6','7')
) as c
where c.o < 3
(7 行受影響)
id cx cy npts pts age
---------- ---------- ---------- ---------- ---------- ----------
960 3023 1422 24 14 6
962 3026 1419 24 14 6
950 3013 1419 59 37 7
949 3010 1423 76 52 7
(4 行受影響)
③ sql中的怎麼選擇數據
要效率建議給table1.項目建立個索引，想必table1.id 和 table2.id一定全是主鍵了，如果不是建立吧
語句上基本沒有什麼好優化的了
④ 急,SQL選擇語句
sql="select * from anli where Elite=True or Elite=False order by Elite,ID desc"
或
sql="select * from anli where Elite=True or Elite=False order by Elite asc,ID desc"
⑤ SQL 選擇查詢
select * from 表名 order by 入學時間(時間格式） asc
⑥ sql選擇語句
select id ,password into :idStr ,into :passwordStr from password where id = '1001'
⑦ SQL選擇語句一個
left join $wpdb->postmeta meta_b on meta_a.post_id=meta_b.post_id
⑧ sql 選擇語句 問題
用 in 表示 字元串是否存在字元串列表中；
（還有 not in)
sql="select top 28 *from data where n_class in ('農業','教育','慈善','新聞','健康','環保','地方','西部','扶貧','活動','城市','視頻') order by n_id desc"
set rs=server.createobject("adodb.recordset")
//注意要加引號
⑨ SQL選擇語句
1、
selectcount(1)blogs_cntfromblogs.websitegroupbyuserid
2、
selectcount(distinctuserid)fromBLOGS.ROLLERUSERa
whereexists(select1fromBLOGS.WEBSITEbwhereb.userid=a.userid)
selectcount(distinctuserid)fromBLOGS.ROLLERUSERa
wherenotexists(select1fromBLOGS.WEBSITEbwhereb.userid=a.userid)