① 关于sql查询代码。
同意“yj003 ”的，可以改进一下：
select [字段名], count(*) AS 数量 from [数据库表名] where [字段名] in (a, b, c ,d) group by [字段名]
② SQL获取表，字段，类型的代码
下面一段是SQLSERVER数据库中获取数据字典的语法，非常全。
SELECT TOP 100 PERCENT --a.id,
CASE WHEN a.colorder = 1 THEN d.name ELSE '' END AS 表名,
CASE WHEN a.colorder = 1 THEN isnull(f.value, '') ELSE '' END AS 表说明,
a.colorder AS 字段序号, a.name AS 字段名, CASE WHEN COLUMNPROPERTY(a.id,
a.name, 'IsIdentity') = 1 THEN '√' ELSE '' END AS 标识,
CASE WHEN EXISTS
(SELECT 1
FROM dbo.sysindexes si INNER JOIN
dbo.sysindexkeys sik ON si.id = sik.id AND si.indid = sik.indid INNER JOIN
dbo.syscolumns sc ON sc.id = sik.id AND sc.colid = sik.colid INNER JOIN
dbo.sysobjects so ON so.name = si.name AND so.xtype = 'PK'
WHERE sc.id = a.id AND sc.colid = a.colid) THEN '√' ELSE '' END AS 主键,
b.name AS 类型, a.length AS 长度, COLUMNPROPERTY(a.id, a.name, 'PRECISION')
AS 精度, ISNULL(COLUMNPROPERTY(a.id, a.name, 'Scale'), 0) AS 小数位数,
CASE WHEN a.isnullable = 1 THEN '√' ELSE '' END AS 允许空, ISNULL(e.text, '')
AS 默认值, ISNULL(g.[value], '') AS 字段说明, d.crdate AS 创建时间,
CASE WHEN a.colorder = 1 THEN d.refdate ELSE NULL END AS 更改时间
FROM dbo.syscolumns a LEFT OUTER JOIN
dbo.systypes b ON a.xtype = b.xusertype INNER JOIN
dbo.sysobjects d ON a.id = d.id AND d.xtype = 'U' AND
d.status >= 0 LEFT OUTER JOIN
dbo.syscomments e ON a.cdefault = e.id LEFT OUTER JOIN
dbo.sysproperties g ON a.id = g.id AND a.colid = g.smallid AND
g.name = 'MS_Description' LEFT OUTER JOIN
dbo.sysproperties f ON d.id = f.
id AND f.smallid = 0 AND
f.name = 'MS_Description'
ORDER BY d.name, a.colorder
③ SYBASE 中 SQL 代码取 所有表的前10行
use sybsystemprocs
go
if exists(select 1 from dbo.sysobjects where name='sp_list_topN_rows' and type='P' )
drop proc sp_list_topN_rows
go
create proc sp_list_topN_rows @num_rows int=null
as
begin
declare @tablename varchar(30),@tablename_prev varchar(30),@sqltext varchar(255)
if (@num_rows is null)
select @num_rows = 10
select top 1 @tablename=name from sysobjects where type='U' order by name
while (@tablename is not null)
begin
select @sqltext="select top " || convert(varchar,@num_rows) || " * from " || @tablename
exec(@sqltext)
select @tablename_prev =@tablename,@tablename=NULL
select top 1 @tablename=name from sysobjects where type='U' and name > @tablename_prev order by name
end
end
go
④ C#中关于sql查询的代码怎么写
string Con = "server=GRQ;uid=;pwd=;database=111 ;";
SqlConnection ConnSql = new SqlConnection( loveDataSet ); //Sql链接类的实例化
ConnSql.Open();//打开数据库
string strSQL = "select * from zong where sign like ' "%+ 文本框里的值 +%"' "; //要执行的SQL语句
SqlDataAdapter da = new SqlDataAdapter(strSQL, ConnSql); //创建DataAdapter数据适配器实例
DataSet ds = new DataSet();//创建DataSet实例
da.Fill(ds, "自定义虚拟表名");
//使用DataAdapter的Fill方法(填充)，调用SELECT命令
dataGridView1.DataSource = ds.Tables[1].DefaultView;
ConnSql.Close();//关闭数据库
⑤ 关于sql数据库查询代码！
假设你这个表有两个字段id(自动增长),name(姓名)，现在要取姓名最后一个数据，可以这样写：
select top 1 name from tablename order by id desc
⑥ 如何用SQL代码提取文件名中的字符后插入表中
存储过程,一个下划线一个下划线切.切完马上存到表里.
步骤:
1.替换后缀
列3 列1 列2
AA1_BB2_CC3
-----------------
2.取第一个下划线前的数据
列3 列1 列2
AA1_BB2_CC3 AA1
-----------------
3.删除列1长度的数据
列3 列1 列2
BB2_CC3 AA1
-----------------
4.取第二下划线数据
列3 列1 列2
BB2_CC3 AA1 BB2
-----------------
列3 列1 列2
CC3 AA1 BB2
-----------------
⑦ 求查询SQL语句代码
你好，SQL语句如下
select NAME,ADDRESS from C表 where NAME in
(select NAME from A表 where NAME not in
(select NAME from B表)
)
简单说明一下：
最外层是直接搜索“姓名，地址”，对NAME有要求
中间一层是搜索在A表中出现的NAME
最内层是排除在A表中出现但又不在B表中的NAME
⑧ C# 求获取Sql各项的正则表达式代码
sql的语法虽然我们平时用的就像 select * from [admin] where id = 2 这句一样，其实还有很多其他的语法也能做到的。
所以这个正则也只能是针对常规的简单SQL语句。
我写了一个，也只是判断了一些常用的SQL关键字。仅作为参考。
string text = "select * from [admin] where aa=1 and cc='b' order by aa desc ";
Regex reg = null;
reg = new Regex(@"\s+from\s+.*?(\s+where\s+|\s+order\s+|\s+group\s+)|\s+from\s+.+", RegexOptions.IgnoreCase);
string table = reg.Match(text).Value;
table = Regex.Replace(table.ToLower(), @"\s+from\s+|\s+where\s+|\[|\]|\s+order\s+|\s+group\s+", "");
reg = new Regex(@"select\s+.*?\s+from\s+", RegexOptions.IgnoreCase);
string field = reg.Match(text).Value;
field = Regex.Replace(field.ToLower(), @"select\s+|\s+from\s+|\[|\]", "");
reg = new Regex(@"\s+where\s+.*?(\s+order\s+|\s+group\s+)|\s+where\s+.+", RegexOptions.IgnoreCase);
string condition = reg.Match(text).Value;
condition = Regex.Replace(condition.ToLower(), @"\s+where\s+|\s+order\s+|\s+group\s+|\[|\]", "");
reg = new Regex(@"\s+order\s+by\s+.*?\s(desc|asc)|\s+order\s+by\s+.*?\s", RegexOptions.IgnoreCase);
string order = reg.Match(text).Value;
order = Regex.Replace(order.ToLower(),@"\s+order\s+by\s+|\[|\]", "");
还有问题可以追问或者HI我。~
⑨ 什么是sql 代码
sql代码是用代码操作数据库，从数据库里把数据取出来，加进去。