Find Replace All String Data in a SQL Server Database - sql-server

Question

I am looking for a script which finds and replaces all fields of type string within a DB with specified text.
The script would for example take the following parameters:
Search for: null
Replace with: empty-string
The primary string data types in SQL Server: Varchar, NVarchar, Text.
This script would then comb through all string based table data and look for in this case null and replace it with a empty string.
Ok I've put together the following code in the meantime.
-- Specify 'dbo' for all tables
DECLARE #schemaName VARCHAR(5) = 'dbo'
BEGIN
DECLARE #tableName VARCHAR(255) -- table name
DECLARE #tableID INT -- table id (aka syst.table.object_id)
DECLARE table_cursor CURSOR FOR
SELECT T.object_id AS TableID, T.name AS TableName FROM sys.tables T
INNER JOIN sys.schemas S ON S.schema_id = T.schema_id
WHERE S.name = #schemaName
OPEN table_cursor
FETCH NEXT FROM table_cursor INTO #tableID, #tableName
WHILE ##FETCH_STATUS = 0
BEGIN
-- construct each tables queries
DECLARE #totalColumnsFound INT = (SELECT COUNT(*) FROM sys.columns C WHERE OBJECT_ID = #tableID
-- text and nvarchar column data types chosen for me (if you need more like ntext, varcahr see sys.types for their ids)
AND (C.system_type_id = 35 OR c.system_type_id = 231))
IF (#totalColumnsFound > 0)
BEGIN
DECLARE #tableUpdateQuery VARCHAR(MAX) = 'update ' + #schemaName + '.' + #tableName + ' set ';
DECLARE #columnName VARCHAR(255) -- column name
DECLARE column_cursor CURSOR FOR
SELECT C.name AS ColumnName FROM sys.columns C WHERE OBJECT_ID = #tableID
-- text and nvarchar column data types chosen for me (if you need more like ntext, varcahr see sys.types for their ids)
AND (C.system_type_id = 35 OR c.system_type_id = 231)
OPEN column_cursor
FETCH NEXT FROM column_cursor INTO #columnName
WHILE ##FETCH_STATUS = 0
BEGIN
-- construct the columns for the update query, piece by piece.
-- This is also where you can apply your logic for how to handle the string update.
-- I am trimming string and updating nulls to empty strings here.
SET #tableUpdateQuery = #tableUpdateQuery + ' ' + #columnName + ' = ltrim(rtrim(isnull(' + #columnName + ',''''))),'
FETCH NEXT FROM column_cursor INTO #columnName
END
CLOSE column_cursor
DEALLOCATE column_cursor
-- trim last comma from string
SET #tableUpdateQuery = LEFT(#tableUpdateQuery, LEN(#tableUpdateQuery) - 1)
/** debuging purposes **
print 'Updating table --> ' + #tableName
print #tableUpdateQuery
print ' '
*/
-- execute dynamic sql
EXEC(#tableUpdateQuery)
END
FETCH NEXT FROM table_cursor INTO #tableID, #tableName
END
CLOSE table_cursor
DEALLOCATE table_cursor
END
--GO

Answer 1

this should help you:
/*
Author: sqiller
Description: Searches for a value to replace in all columns from all tables
USE: EXEC dbo.usp_Update_AllTAbles 'work', 'sqiller', 1
#search = Value to look for Replace
#newvalue = the value that will replace #search
#Test = If set to 1, it will only PRINT the UPDATE statement instead of EXEC, useful to see
what is going to update before.
*/
CREATE PROCEDURE dbo.usp_Update_AllTAbles(
#search varchar(100),
#newvalue varchar(100),
#Test bit)
AS
BEGIN
IF NOT EXISTS (select 1 from INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 'Tables_to_Update')
BEGIN
CREATE TABLE dbo.Tables_to_Update(
Table_name varchar(100),
Column_name varchar(100),
recordsToUpdate int
)
END
DECLARE #table varchar(100)
DECLARE #column varchar(100)
DECLARE #SQL varchar(max)
SELECT TABLE_SCHEMA+'.'+TABLE_NAME as Table_Name, 0 as Processed INTO #tables from information_schema.tables WHERE TABLE_TYPE != 'VIEW'
WHILE EXISTS (select * from #tables where processed = 0)
BEGIN
SELECT top 1 #table = table_name from #tables where processed = 0
SELECT column_name, 0 as Processed INTO #columns from information_schema.columns where TABLE_SCHEMA+'.'+TABLE_NAME = #table
WHILE EXISTS (SELECT * from #columns where processed = 0)
BEGIN
SELECT top 1 #column = COLUMN_NAME from #columns where processed = 0
SET #SQL = 'INSERT INTO Tables_to_Update
select '''+ #table +''', '''+ #column +''', count(*) from '+#table+ ' where '+ #column +' like ''%'+ #search +'%'''
EXEC(#SQL)
IF EXISTS (SELECT * FROM Tables_to_Update WHERE Table_name = #table)
BEGIN
SET #SQL = 'UPDATE '+ #table + ' SET '+ #column + ' = REPLACE('''+#column+''','''+#search+''','''+ #newvalue +''') WHERE '+ #column + ' like ''%'+#search+'%'''
--UPDATE HERE
IF (#Test = 1)
BEGIN
PRINT #SQL
END
ELSE
BEGIN
EXEC(#SQL)
END
END
UPDATE #columns SET Processed = 1 where COLUMN_NAME = #column
END
DROP TABLE #columns
UPDATE #tables SET Processed = 1 where table_name = #table
END
SELECT * FROM Tables_to_Update where recordsToUpdate > 0
END

Answer 2

The following will find and replace a string in every database (excluding system databases) on every table on the instance you are connected to:
Simply change 'Search String' to whatever you seek and 'Replace String' with whatever you want to replace it with.
--Getting all the databases and making a cursor
DECLARE db_cursor CURSOR FOR
SELECT name
FROM master.dbo.sysdatabases
WHERE name NOT IN ('master','model','msdb','tempdb') -- exclude these databases
DECLARE #databaseName nvarchar(1000)
--opening the cursor to move over the databases in this instance
OPEN db_cursor
FETCH NEXT FROM db_cursor INTO #databaseName
WHILE ##FETCH_STATUS = 0
BEGIN
PRINT #databaseName
--Setting up temp table for the results of our search
DECLARE #Results TABLE(TableName nvarchar(370), RealColumnName nvarchar(370), ColumnName nvarchar(370), ColumnValue nvarchar(3630))
SET NOCOUNT ON
DECLARE #SearchStr nvarchar(100), #ReplaceStr nvarchar(100), #SearchStr2 nvarchar(110)
SET #SearchStr = 'Search String'
SET #ReplaceStr = 'Replace String'
SET #SearchStr2 = QUOTENAME('%' + #SearchStr + '%','''')
DECLARE #TableName nvarchar(256), #ColumnName nvarchar(128)
SET #TableName = ''
--Looping over all the tables in the database
WHILE #TableName IS NOT NULL
BEGIN
DECLARE #SQL nvarchar(2000)
SET #ColumnName = ''
DECLARE #result NVARCHAR(256)
SET #SQL = 'USE ' + #databaseName + '
SELECT #result = MIN(QUOTENAME(TABLE_SCHEMA) + ''.'' + QUOTENAME(TABLE_NAME))
FROM [' + #databaseName + '].INFORMATION_SCHEMA.TABLES
WHERE TABLE_TYPE = ''BASE TABLE'' AND TABLE_CATALOG = ''' + #databaseName + '''
AND QUOTENAME(TABLE_SCHEMA) + ''.'' + QUOTENAME(TABLE_NAME) > ''' + #TableName + '''
AND OBJECTPROPERTY(
OBJECT_ID(
QUOTENAME(TABLE_SCHEMA) + ''.'' + QUOTENAME(TABLE_NAME)
), ''IsMSShipped''
) = 0'
EXEC master..sp_executesql #SQL, N'#result nvarchar(256) out', #result out
SET #TableName = #result
PRINT #TableName
WHILE (#TableName IS NOT NULL) AND (#ColumnName IS NOT NULL)
BEGIN
DECLARE #ColumnResult NVARCHAR(256)
SET #SQL = '
SELECT #ColumnResult = MIN(QUOTENAME(COLUMN_NAME))
FROM [' + #databaseName + '].INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = PARSENAME(''[' + #databaseName + '].' + #TableName + ''', 2)
AND TABLE_NAME = PARSENAME(''[' + #databaseName + '].' + #TableName + ''', 1)
AND DATA_TYPE IN (''char'', ''varchar'', ''nchar'', ''nvarchar'')
AND TABLE_CATALOG = ''' + #databaseName + '''
AND QUOTENAME(COLUMN_NAME) > ''' + #ColumnName + ''''
PRINT #SQL
EXEC master..sp_executesql #SQL, N'#ColumnResult nvarchar(256) out', #ColumnResult out
SET #ColumnName = #ColumnResult
PRINT #ColumnName
IF #ColumnName IS NOT NULL
BEGIN
INSERT INTO #Results
EXEC
(
'USE ' + #databaseName + '
SELECT ''' + #TableName + ''',''' + #ColumnName + ''',''' + #TableName + '.' + #ColumnName + ''', LEFT(' + #ColumnName + ', 3630)
FROM ' + #TableName + ' (NOLOCK) ' +
' WHERE ' + #ColumnName + ' LIKE ' + #SearchStr2
)
END
END
END
--Declaring another temporary table
DECLARE #time_to_update TABLE(TableName nvarchar(370), RealColumnName nvarchar(370))
INSERT INTO #time_to_update
SELECT TableName, RealColumnName FROM #Results GROUP BY TableName, RealColumnName
DECLARE #MyCursor CURSOR;
BEGIN
DECLARE #t nvarchar(370)
DECLARE #c nvarchar(370)
--Looping over the search results
SET #MyCursor = CURSOR FOR
SELECT TableName, RealColumnName FROM #time_to_update GROUP BY TableName, RealColumnName
--Getting my variables from the first item
OPEN #MyCursor
FETCH NEXT FROM #MyCursor
INTO #t, #c
WHILE ##FETCH_STATUS = 0
BEGIN
-- Updating the old values with the new value
DECLARE #sqlCommand varchar(1000)
SET #sqlCommand = '
USE ' + #databaseName + '
UPDATE [' + #databaseName + '].' + #t + ' SET ' + #c + ' = REPLACE(' + #c + ', ''' + #SearchStr + ''', ''' + #ReplaceStr + ''')
WHERE ' + #c + ' LIKE ''' + #SearchStr2 + ''''
PRINT #sqlCommand
BEGIN TRY
EXEC (#sqlCommand)
END TRY
BEGIN CATCH
PRINT ERROR_MESSAGE()
END CATCH
--Getting next row values
FETCH NEXT FROM #MyCursor
INTO #t, #c
END;
CLOSE #MyCursor ;
DEALLOCATE #MyCursor;
END;
DELETE FROM #time_to_update
DELETE FROM #Results
FETCH NEXT FROM db_cursor INTO #databaseName
END
CLOSE db_cursor
DEALLOCATE db_cursor
Note: this isn't ideal, nor is it optimized

Answer 3

Here is another answer, similar to above (and hopefully more readable/efficient), since I recently had a similar requirement and this is how I solved it.
CREATE OR ALTER PROCEDURE UPDATE_ALL_COLUMNS
#TableNameSearchFilter NVARCHAR(100),
#TableSchema NVARCHAR(100),
#TestValue NVARCHAR(100),
#NewValue NVARCHAR(100)
AS
BEGIN
DECLARE #NRCOLUMNS INT;
DECLARE #i INT = 0;
DECLARE #COLUMN NVARCHAR(100) = '';
DECLARE #SQL NVARCHAR(MAX) = '';
DECLARE #TableToUpdate NVARCHAR(256) = '';
DECLARE #insertingNULL BIT;
IF (#NewValue IS NULL) SET #insertingNULL = 1
ELSE SET #insertingNULL = 0;
WHILE #TableToUpdate IS NOT NULL
BEGIN
SELECT #TableToUpdate = MIN(TABLE_NAME)
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE #TableNameSearchFilter
AND TABLE_SCHEMA = #TableSchema
AND TABLE_NAME > #TableToUpdate;
WITH CTE1 AS
(
SELECT ROW_NUMBER() OVER (ORDER BY ORDINAL_POSITION) AS RN
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = #TableToUpdate
AND TABLE_SCHEMA = #TableSchema
AND (#insertingNULL = 0 OR (#insertingNULL = 1 AND IS_NULLABLE = 'YES'))
)
SELECT #i = MIN(RN), #NRCOLUMNS = MAX(RN) FROM CTE1;
WHILE (#i <= #NRCOLUMNS AND #TableToUpdate IS NOT NULL)
BEGIN
WITH CTE AS
(
SELECT *, ROW_NUMBER() OVER (ORDER BY ORDINAL_POSITION) AS RN
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = #TableToUpdate
AND TABLE_SCHEMA = #TableSchema
AND (#insertingNULL = 0 OR (#insertingNULL = 1 AND IS_NULLABLE = 'YES'))
)
SELECT #COLUMN = COLUMN_NAME
FROM CTE
WHERE RN = #i;
SET #SQL = #SQL +
N'UPDATE D SET ' + #COLUMN + N' = ' + ISNULL(N'''' + #NewValue + N'''', N'NULL')
+ N' FROM ' + #TableSchema + N'.' + #TableToUpdate + N' D WHERE CAST(D.' + #COLUMN + ' AS NVARCHAR) = ' + ISNULL(N'''' + #TestValue + N'''', N'NULL') + ';'
+ NCHAR(13) + NCHAR(10);
SET #i = #i + 1;
END;
END;
--PRINT SUBSTRING(#SQL, 1, 4000)
--PRINT SUBSTRING(#SQL, 4001, 8000)
--PRINT SUBSTRING(#SQL, 8001, 12000)
--PRINT SUBSTRING(#SQL, 12001, 16000)
--PRINT SUBSTRING(#SQL, 16001, 20000)
--PRINT SUBSTRING(#SQL, 20001, 24000)
EXEC (#SQL)
END
GO
As a usage example:
EXEC UPDATE_ALL_COLUMNS '%temp%', 'dbo', '', NULL
Parameters:
#TableNameSearchFilter - this will be used with the LIKE operator to find all the tables from your database whose names that match this value;
#TableSchema - the schema of the table (usually dbo)
#TestValue - the value to search for in ALL of the columns (and rows) of each found table;
#NewValue - the value to replace #TestValue with. Can also be NULL.
Explanation:
The EXEC statement will find ALL tables whose names contain the word 'temp', on the 'dbo' schema of your database, then search for the value '' (empty string) in ALL columns of ALL of the found tables, then replace this value with a NULL.
Obviously, if you have long(er) column/table names or the update value, make sure to update the limits on the parameters.
Make sure to first comment the last line (EXEC (#SQL)) and uncomment the lines with PRINT, just to get an idea for what the procedure does and how the final statements look like.
This is not going to work (most likely) if you want to search for the NULL value (i.e. to have #TestValue as NULL). Nevertheless, it can be easily changed to accomplish this as well, by replacing the equal sign from the WHERE clause (in the dynamic query) with IS NULL and removing the rest of the line, when #TestValue IS NULL.
Can be easily adapted to search for columns of only certain types (like VARCHAR etc).
The procedure accounts for inserting NULL values, and will only do so in NULLABLE columns.