這篇文章給大家分享的是有關(guān)SQL Server如何查找表名或列名中包含空格的表和列的內(nèi)容。小編覺(jué)得挺實(shí)用的,因此分享給大家做個(gè)參考,一起跟隨小編過(guò)來(lái)看看吧。

如下案例所示:
USE TEST; GO --表TEST_COLUMN中兩個(gè)字段都包含有空格 CREATE TABLE TEST_COLUMN ( "ID " INT IDENTITY (1,1), [Name ] VARCHAR(32), [Normal] VARCHAR(32) ); GO --表[TEST_TABLE ]中包含空格, 里面對(duì)應(yīng)三個(gè)字段,一個(gè)前面包含空格(后面詳細(xì)闡述),一個(gè)字段中間包含空格,一個(gè)字段后面包含空格。 CREATE TABLE [TEST_TABLE ] ( [ F_NAME] NVARCHAR(32), [M NAME] NVARCHAR(32), [L_NAME ] NVARCHAR(32) ) GO
實(shí)現(xiàn)方法:
那么要如何找出表名或字段名包含空格的相關(guān)信息呢? 不管是常規(guī)方法還是正則表達(dá)式,這個(gè)都會(huì)效率不高。我們可以用一個(gè)取巧的方法,就是通過(guò)字段的字符數(shù)和字節(jié)數(shù)的規(guī)律來(lái)判斷,如果沒(méi)有包含空格,那么列名的字節(jié)數(shù)和字符數(shù)滿(mǎn)足下面規(guī)律(表名也是如此):
DATALENGTH(name) = 2* LEN(name)
SELECT name ,
DATALENGTH(name) AS NAME_BYTES ,
LEN(name) AS NAME_CHARACTER
FROM sys.columns
WHERE object_id = OBJECT_ID('TEST_COLUMN');
clip_image001
原理是這樣的,保存這些元數(shù)據(jù)的字段類(lèi)型為sysname ,其實(shí)這個(gè)系統(tǒng)數(shù)據(jù)類(lèi)型,用于定義表列、變量以及存儲(chǔ)過(guò)程的參數(shù),是nvarchar(128)的同義詞。所以一個(gè)字母占2個(gè)字節(jié)。那么我們安裝這個(gè)規(guī)律寫(xiě)了一個(gè)腳本來(lái)檢查數(shù)據(jù)中那些表名或字段名包含空格。方便巡檢。如下測(cè)試所示
IF OBJECT_ID('tempdb.dbo.#TabColums') IS NOT NULL
DROP TABLE dbo.#TabColums;
CREATE TABLE #TabColums
(
object_id INT ,
column_id INT
)
INSERT INTO #TabColums
SELECT object_id ,
column_id
FROM sys.columns
WHERE DATALENGTH(name) != LEN(name) * 2
SELECT
TL.name AS TableName,
C.Name AS FieldName,
T.Name AS DataType,
DATALENGTH(C.name) AS COLUMN_DATALENGTH,
LEN(C.name) AS COLUMN_LENGTH,
CASE WHEN C.Max_Length = -1 THEN 'Max' ELSE CAST(C.Max_Length AS VARCHAR) END AS Max_Length,
CASE WHEN C.is_nullable = 0 THEN '×' ELSE N'√' END AS Is_Nullable,
C.is_identity,
ISNULL(M.text, '') AS DefaultValue,
ISNULL(P.value, '') AS FieldComment
FROM sys.columns C
INNER JOIN sys.types T ON C.system_type_id = T.user_type_id
LEFT JOIN dbo.syscomments M ON M.id = C.default_object_id
LEFT JOIN sys.extended_properties P ON P.major_id = C.object_id AND C.column_id = P.minor_id
INNER JOIN sys.tables TL ON TL.object_id = C.object_id
INNER JOIN #TabColums TC ON C.object_id = TC.object_id AND c.column_id = TC.column_id
ORDER BY C.Column_Id ASC
那么為什么表名TEST_TABLE的三個(gè)字段里面,前面包含空格與與中間包含空格都識(shí)別不出來(lái)呢?這個(gè)與數(shù)據(jù)庫(kù)的LEN函數(shù)有關(guān)系,LEN函數(shù)返回指定字符串表達(dá)式的字符數(shù),其中
不包含尾隨空格。所以這個(gè)腳本是無(wú)法排查表名或字段名前面包含空格的。如果要排查這種情況,就需要使用下面SQL腳本(中間包含空格在此略過(guò),這個(gè)不符合命名規(guī)則):
SELECT * FROM sys.columns WHERE NAME LIKE ' %' --字段前面包含空格。

其實(shí)到了這一步,還沒(méi)有完,如果一個(gè)實(shí)例,里面有十幾個(gè)數(shù)據(jù)庫(kù),那么使用上面這個(gè)腳本,我要切換數(shù)據(jù)庫(kù),執(zhí)行十幾次,對(duì)于我這種懶人來(lái)說(shuō),我覺(jué)得無(wú)法忍受的。那么必須寫(xiě)
一個(gè)腳本,將所有數(shù)據(jù)庫(kù)全部檢查完。本來(lái)想用sys.sp_MSforeachdb,但是這個(gè)內(nèi)部存儲(chǔ)過(guò)程有一些限制,遂寫(xiě)了下面腳本。
DECLARE @db_name NVARCHAR(32);
DECLARE @sql_text NVARCHAR(MAX);
DECLARE @db TABLE
(
database_name NVARCHAR(64)
);
IF OBJECT_ID('tempdb.dbo.#TabColums') IS NOT NULL
DROP TABLE dbo.#TabColums;
CREATE TABLE #TabColums
(
object_id INT ,
column_id INT
);
INSERT INTO @db
SELECT name FROM sys.databases WHERE state_desc='ONLINE' AND database_id !=2;
WHILE (1=1)
BEGIN
SELECT TOP 1 @db_name = database_name FROM @db ORDER BY 1;
IF @@ROWCOUNT = 0 RETURN;
SET @sql_text =N'USE ' + @db_name +';
TRUNCATE TABLE #TabColums;
INSERT INTO #TabColums
SELECT object_id ,
column_id
FROM sys.columns
WHERE DATALENGTH(name) != LEN(name) * 2;
SELECT ''' + @db_name + ''' AS DatabaseName,
TL.name AS TableName ,
C.name AS FieldName ,
T.name AS DataType ,
DATALENGTH(C.name) AS COLUMN_DATALENGTH ,
LEN(C.name) AS COLUMN_LENGTH ,
CASE WHEN C.max_length = -1 THEN ''Max''
ELSE CAST(C.max_length AS VARCHAR)
END AS Max_Length ,
CASE WHEN C.is_nullable = 0 THEN ''×''
ELSE ''√''
END AS Is_Nullable ,
C.is_identity ,
ISNULL(M.text, '''') AS DefaultValue ,
ISNULL(P.value, '''') AS FieldComment
FROM sys.columns C
INNER JOIN sys.types T ON C.system_type_id = T.user_type_id
LEFT JOIN dbo.syscomments M ON M.id = C.default_object_id
LEFT JOIN sys.extended_properties P ON P.major_id = C.object_id
AND C.column_id = P.minor_id
INNER JOIN sys.tables TL ON TL.object_id = C.object_id
INNER JOIN #TabColums TC ON C.object_id = TC.object_id
AND C.column_id = TC.column_id
ORDER BY C.column_id ASC;';
PRINT(@sql_text);
EXECUTE(@sql_text);
DELETE FROM @db WHERE database_name=@db_name;
END
TRUNCATE TABLE #TabColums;
DROP TABLE #TabColums;另外,對(duì)應(yīng)表名而言,可以使用下面腳本。在此略過(guò),不做過(guò)多介紹!
DECLARE @db_name NVARCHAR(32); DECLARE @sql_text NVARCHAR(MAX); DECLARE @db TABLE ( database_name NVARCHAR(64) ); INSERT INTO @db SELECT name FROM sys.databases WHERE state_desc='ONLINE' AND database_id !=2; WHILE (1=1) BEGIN SELECT TOP 1 @db_name = database_name FROM @db ORDER BY 1; IF @@ROWCOUNT = 0 RETURN; SET @sql_text =N'USE ' + @db_name +'; SELECT ''' + @db_name + ''' as database_name, name, DATALENGTH(name) as table_name_bytes, LEN(name) as table_name_character, type_desc,create_date,modify_date FROM sys.tables WHERE DATALENGTH(name) != LEN(name) * 2; '; PRINT(@sql_text); EXECUTE(@sql_text); DELETE FROM @db WHERE database_name=@db_name; END
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