我需要帮助。我能够手动完成要求,但希望这可以自动化。请看下面。
CREATE TABLE TblMaster (CName varchar(30), Flag int) INSERT INTO TblMaster (cname,flag) values ('ABC',0); INSERT INTO TblMaster (cname,flag) values ('DEF',1); INSERT INTO TblMaster (cname,flag) values ('GHI',1); INSERT INTO TblMaster (cname,flag) values ('JKL',1); INSERT INTO TblMaster (cname,flag) values ('MNO',1);
CREATE TABLE TB1 ( ABC int , ABC1 int, ABC2 int, DEF varchar(30), DEF1 varchar(30), DEF2 varchar(30), GHI varchar(30), GHI1 varchar(30), JKL numeric, JKL1 numeric, MNO datetime, MNO1 datetime, NOTEXIST varchar(30), NOTEXIST1 varchar(30), NOTEXIST2 varchar(30) ) INSERT INTO TB1 values (0,1,2,'d1','d2','d3','g1','g2',0.0,1.0,null,null,Null,NUll,Null) INSERT INTO TB1 values (0,1,2,'d1','d2','d3','g1','g2',0.0,1.0,null,null,Null,NUll,Null) INSERT INTO TB1 values (0,1,2,'d1','d2','d3','g1','g2',0.0,1.0,null,null,Null,NUll,Null) INSERT INTO TB1 values (0,1,2,'d1','d2','d3','g1','g2',0.0,1.0,null,null,Null,NUll,Null) CREATE TABLE TB2 ( ABC int , ABC1 int, ABC2 int, DEF varchar(30), DEF1 varchar(30), DEF2 varchar(30), GHI varchar(30), GHI1 varchar(30), JKL numeric, JKL1 numeric, MNO datetime, MNO1 datetime, NOTEXIST varchar(30), NOTEXIST1 varchar(30), NOTEXIST2 varchar(30) ) INSERT INTO TB2 values (0,1,2,'d1','d2','d3','g1','g2',0.0,1.0,null,null,Null,NUll,Null) INSERT INTO TB2 values (0,1,2,'d1','d2','d3','g1','g2',0.0,1.0,null,null,Null,NUll,Null) INSERT INTO TB2 values (0,1,2,'d1','d2','d3','g1','g2',0.0,1.0,null,null,Null,NUll,Null) INSERT INTO TB2 values (0,1,2,'d1','d2','d3','g1','g2',0.0,1.0,null,null,Null,NUll,Null)
Select CName from TblMaster where FLAG = 1
This yields result:
DEF
GHI
JKL
MNO
湾使用上面4.a中的结果来识别DB中具有相似字符串内容(值)的其他表中的列名。下面的代码剪切选择'DEF'的值
SELECT t.name AS table_name,c.name AS column_name
FROM sys.tables AS t
INNER JOIN sys.columns c ON t.OBJECT_ID = c.OBJECT_ID
WHERE c.name LIKE '%DEF%' and t.name in ('TB1','TB2')
ORDER BY table_name;
This yields result:
table_name column_name
TB1 DEF
TB1 DEF1
TB1 DEF2
TB2 DEF
TB2 DEF1
TB2 DEF2
Similarly repeat the above for 'GHI', 'JKL', 'MNO'.
C。删除步骤4.b中标识的表中的列(所有结果)。
ALTER TABLE TB1
DROP COLUMN
DEF,DEF1,DEF2,GHI,GHI1,JKL, JKL1,MNO,MNO1
ALTER TABLE TB2
DROP COLUMN
DEF,DEF1,DEF2,GHI,GHI1,JKL, JKL1,MNO,MNO1
提前致谢!!
以下是我尝试过的但是没有用。请帮忙。
DECLARE @cnt INT = 0
DECLARE @tempcnt INT = 1
DECLARE @tempcname varchar(30)
/* Find the max number of count for which we need to check other tables */
SELECT @cnt = COUNT (*) FROM TblMaster WHERE flag = 1
/* Create a temporary table with Row Number and the Column that we need */
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS id, CName
INTO #TempTable
FROM (SELECT * FROM TblMaster WHERE flag = 1) t;
/* Loop through the temporary table to process each CName */
WHILE @tempcnt <= @cnt
BEGIN
SELECT @tempcname = CName
FROM #TempTable WHERE id = @tempcnt
/* PRINT @tempcname */
/* Identify the Columns that have CName string as Column Name in other
tables */
ALTER TABLE TB1
DROP COLUMN
(
SELECT c.name AS column_name
FROM sys.tables AS t
INNER JOIN sys.columns c ON t.OBJECT_ID = c.OBJECT_ID
WHERE c.name LIKE %@tempcname% and t.name = TB1
)
ALTER TABLE TB2
DROP COLUMN
(
SELECT c.name AS column_name
FROM sys.tables AS t
INNER JOIN sys.columns c ON t.OBJECT_ID = c.OBJECT_ID
WHERE c.name LIKE %@tempcname% and t.name = TB2
)
SET @tempcnt = @tempcnt + 1;
END;
DROP TABLE #TempTable;
检查此过程是否按预期工作。
看看小提琴,(你会在底部找到一个链接)。
我使用了双动态查询。
第一个返回相似列的逗号分隔列表。
SELECT @columns = STUFF((SELECT ',' + COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE (COLUMN_NAME LIKE '%DEF%' OR COLUMN_NAME LIKE '%GHI%' OR COLUMN_NAME LIKE '%JKL%' OR COLUMN_NAME LIKE '%MNO%') AND TABLE_NAME = 'TB1'
FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'), 1, 1, '')
通过删除列来第二次查询alter table:
ALTER TABLE TB1 DROP COLUMN DEF,DEF1,DEF2,GHI,GHI1,JKL,JKL1,MNO,MNO1
这是功能:
CREATE PROCEDURE dbo.DropColumns(@table_name NVARCHAR(128)) AS BEGIN DECLARE @cmd NVARCHAR(MAX); DECLARE @colsOR NVARCHAR(MAX); DECLARE @cols NVARCHAR(MAX); -- filter used in WHERE clause (COLUMN_NAME LIKE '%REF%' OR ...) SET @colsOR = STUFF((SELECT ' OR ' + CONCAT('COLUMN_NAME LIKE ''%', CName, '%''') FROM TblMaster WHERE FLAG = 1 FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'), 1, 4, ''); -- columns returned separated by comma DEF,DEF1,DEF2,GHI,GHI1,JKL,JKL1,MNO,MNO1 SET @cmd = 'SELECT @columns = STUFF((SELECT '','' + COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE (' + @colsOR + ') AND TABLE_NAME = ''' + @table_name + ''' FOR XML PATH(''''), TYPE).value(''.'', ''NVARCHAR(MAX)''), 1, 1, '''')' EXEC sp_executesql @cmd, N'@columns NVARCHAR(MAX) OUTPUT', @columns = @cols OUTPUT; SET @cmd = 'ALTER TABLE ' + @table_name + ' DROP COLUMN ' + @cols; EXEC sp_executesql @cmd; RETURN 0; END GO
✓
EXEC dbo.DropColumns @table_name = 'TB1'; GO
✓
--check results SELECT TABLE_NAME, COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'TB1'; GO
TABLE_NAME | COLUMN_NAME :--------- | :---------- TB1 | ABC TB1 | ABC1 TB1 | ABC2 TB1 | NOTEXIST TB1 | NOTEXIST1 TB1 | NOTEXIST2
dbfiddle here