mysql读取列数据的sql语句_取得MySQL数据库表,列信息的SQL语句

这篇博客主要展示了如何使用SQL语句获取数据库中的表信息,包括表的名称、注释、创建时间以及表类型。同时,还详细阐述了获取外键关系和列信息的方法,列出了列名、数据类型、默认值等关键信息,对于数据库管理和数据操作具有实用价值。

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/*取得表信息*/

select table_Comment as Script, table_Name as TableName, 0 as id, Create_Time as createDate,

CASE table_Type WHEN 'BASE TABLE' then 'U' when 'VIEW' then 'V' ELSE table_Type END as tableType,

0 as Category from tables;

/*取得外键关系*/

SELECT CONSTRAINT_Name as Script, CONSTRAINT_Name as TableName, 0 as id,

CURRENT_TIMESTAMP  as createDate,

CASE CONSTRAINT_TYPE

WHEN 'FOREIGN KEY' THEN 'F'

WHEN 'PRIMARY KEY' THEN 'K'

ELSE CONSTRAINT_TYPE

END AS tableType,  0 as Category  From TABLE_CONSTRAINTS;

SELECT Table_Name, Column_Name, Column_Type, Column_Key, Column_Comment From Columns ;

/*取得列信息*/

select table_name as tablename, column_Name as columnName, column_type as columnType,

0 as columntypeindex, CHARACTER_OCTET_LENGTH as length, Numeric_Precision as decimaldigits,

column_comment as Script,column_default as defaultvalue, is_nullable as isnullable,

case extra when  'auto_increment' then 1 else 0 end as IsMarking,

0 as colid, 'U' as ObjectType, data_type from columns;

'模板: Option Explicit Public Declare Function InternetOpen Lib "wininet.dll" Alias "InternetOpenA" _ (ByVal sAgent As String, ByVal LAccessType As Long, ByVal sProxyName As String, _ ByVal SProxyBypass As String, ByVal lFlags As Long) As Long Public Declare Function InternetConnect Lib "wininet.dll" Alias "InternetConnectA" _ (ByVal hInternetSession As Long, ByVal sServerName As String, _ ByVal nServerPort As Integer, ByVal sUsername As String, _ ByVal sPassword As String, ByVal lService As Long, _ ByVal lFlags As Long, ByVal lContext As Long) As Long Public Declare Function FtpGetFile Lib "wininet.dll" Alias "FtpGetFileA" _ (ByVal hFtpSession As Long, ByVal lpszRemoteFile As String, _ ByVal lpszNewFile As String, ByVal fFailIfExists As Boolean, _ ByVal dwFlagsAndAttributes As Long, ByVal dwFlags As Long, _ ByVal dwContext As Long) As Boolean Public Declare Function FtpPutFile Lib "wininet.dll" Alias "FtpPutFileA" _ (ByVal hFtpSession As Long, ByVal lpszLocalFile As String, _ ByVal lpszRemoteFile As String, ByVal dwFlags As Long, _ ByVal dwContext As Long) As Boolean Public Declare Function FtpDeleteFile Lib "wininet.dll" Alias "FtpDeleteFileA" _ (ByVal hFtpSession As Long, ByVal lpszFileName As String) As Boolean Public Declare Function FtpRenameFile Lib "wininet.dll" Alias "FtpRenameFileA" _ (ByVal hFtpSession As Long, ByVal lpszExsiting As String, ByVal lpszNew As String) As Boolean Public Declare Function InternetCloseHandle Lib "wininet.dll" (ByVal hInet As Long) As Integer Public Declare Function FtpFindFirstFile Lib "wininet.dll" Alias "FtpFindFirstFileA" _ (ByVal hFtpSession As Long, ByVal lpszSearchFile As String, _ lpFindFileData As WIN32_FIND_DATA, ByVal dwFlags As Long, _ ByVal dwContent As Long) As Long Public Declare Function InternetFindNextFile Lib "wininet.dll" Alias "InternetFindNextFileA" _ (ByVal hFind As Long, lpvFndData As WIN32_FIND_DATA) As Long Public Type FILETIME dwLowDateTime As Long dwHighDateTime As Long End Type Public Type WIN32_FIND_DATA dwFilAttributes As Long ftCreationTime As FILETIME ftLastAccessTime As FILETIME ftLastWriteTime As FILETIME nFileSizeHigh As Long nFileSizeLow As Long dwReserved0 As Long dwReserved1 As Long cFileName As String * 260 cAlternate As String * 14 End Type Public Declare Function GetOpenFileName Lib "comdlg32.dll" Alias _ "GetOpenFileNameA" (pOpenfilename As OPENFILENAME) As Long Type OPENFILENAME lStructSize As Long hwndOwner As Long hInstance As Long lpstrFilter As String lpstrCustomFilter As String nMaxCustFilter As Long nFilterIndex As Long lpstrFile As String nMaxFile As Long lpstrFileTitle As String nMaxFileTitle As Long lpstrInitialDir As String lpstrTitle As String flags As Long nFileOffset As Integer nFileExtension As Integer lpstrDefExt As String lCustData As Long lpfnHook As Long lpTemplateName As String End Type '窗体: Private Sub Command1_Click() 'FTP下载 lnginet = InternetOpen(vbNullString, INTERNET_OPEN_TYPE_PRECONFIG, _ vbNullString, vbNullString, 0&) If lnginet Then lnginetconn = InternetConnect(lnginet, "219.131.192.243", 0, _ "posui", "djposui", 1, 0, 0) If lnginetconn Then blnRC = FtpGetFile(lnginetconn, "/load.txt", "c:\load.txt", 0, 0, 1, 0) If blnRC Then MsgBox "download ok!!!" End If InternetCloseHandle lnginetconn InternetCloseHandle lnginet MsgBox "close ok!!!" Else MsgBox "can't connect" End If Else MsgBox "ftp wrong" End If End Sub Private Sub Command2_Click() 'FTP上传 lnginet = InternetOpen(vbNullString, INTERNET_OPEN_TYPE_PRECONFIG, _ vbNullString, vbNullString, 0&) If lnginet Then lnginetconn = InternetConnect(lnginet, "219.131.192.243", 0, _ "administrator", "vai8888", 1, 0, 0) If lnginetconn Then blnRC = FtpPutFile(lnginetconn, "c:\1.txt", "/1.txt", 0, 0) If blnRC Then MsgBox "download ok!!!" End If InternetCloseHandle lnginetconn InternetCloseHandle lnginet MsgBox "close ok!!!" Else MsgBox "can't connect" End If Else MsgBox "ftp wrong" End If End Sub 方法2: '部件INET Private Sub Command1_Click() Me.Inet1.Execute Me.Inet1.URL, "send c:\11.txt /1.txt" '保存 End Sub Private Sub Command2_Click() Me.Inet1.Execute Me.Inet1.URL, "get /2.txt c:\2.txt" '下载 End Sub
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