Find-DbaSimilarTable

Synopsis

Finds tables and views with similar structures by comparing column names across databases

Description

Analyzes table and view structures across databases by comparing column names using INFORMATION_SCHEMA views. Returns a match percentage showing how similar structures are based on shared column names.

Perfect for finding archive tables that mirror production structures, identifying tables that might serve similar purposes across databases, or discovering where specific table patterns are used throughout your SQL Server environment.

You can search across all databases or target specific databases, schemas, or tables. The function calculates match percentages so you can set minimum thresholds to filter results and focus on the most relevant matches.

More information can be found here: https://sqljana.wordpress.com/2017/03/31/sql-server-find-tables-with-similar-table-structure/

Syntax

Find-DbaSimilarTable
    [-SqlInstance] <DbaInstanceParameter[]>
    [[-SqlCredential] <PSCredential>]
    [[-Database] <Object[]>]
    [[-ExcludeDatabase] <Object[]>]
    [[-SchemaName] <String>]
    [[-TableName] <String>]
    [-ExcludeViews]
    [-IncludeSystemDatabases]
    [[-MatchPercentThreshold] <Int32>]
    [-EnableException]
    [<CommonParameters>]

Examples

Example: 1

PS C:\> Find-DbaSimilarTable -SqlInstance DEV01

Searches all user database tables and views for each, returns all tables or views with their matching tables/views and match percent

Example: 2

PS C:\> Find-DbaSimilarTable -SqlInstance DEV01 -Database AdventureWorks

Searches AdventureWorks database and lists tables/views and their corresponding matching tables/views with match percent

Example: 3

PS C:\> Find-DbaSimilarTable -SqlInstance DEV01 -Database AdventureWorks -SchemaName HumanResource

Searches AdventureWorks database and lists tables/views in the HumanResource schema with their corresponding matching tables/views with match percent

Example: 4

PS C:\> Find-DbaSimilarTable -SqlInstance DEV01 -Database AdventureWorks -SchemaName HumanResource -Table Employee

Searches AdventureWorks database and lists tables/views in the HumanResource schema and table Employee with its corresponding matching tables/views with match percent

Example: 5

PS C:\> Find-DbaSimilarTable -SqlInstance DEV01 -Database AdventureWorks -MatchPercentThreshold 60

Searches AdventureWorks database and lists all tables/views with its corresponding matching tables/views with match percent greater than or equal to 60

Required Parameters

-SqlInstance

The target SQL Server instance or instances. This can be a collection and receive pipeline input

Optional Parameters

-SqlCredential

Login to the target instance using alternative credentials. Accepts PowerShell credentials (Get-Credential).
Windows Authentication, SQL Server Authentication, Active Directory - Password, and Active Directory - Integrated are all supported.
For MFA support, please use Connect-DbaInstance.

-Database

Specifies which databases to search for similar table structures. Accepts multiple database names.
Use this to limit the search scope when you know which databases contain the tables you’re comparing.

-ExcludeDatabase

Excludes specific databases from the similarity search. Accepts multiple database names.
Useful for skipping temp databases, development copies, or databases with known irrelevant structures.

-SchemaName

Limits the search to tables within a specific schema. Only tables in this schema will be used as reference structures.
Use this when comparing tables within a logical grouping like ‘Sales’, ‘HR’, or ‘Archive’ schemas.

-TableName

Uses a specific table as the reference structure to find similar tables across databases.
Perfect for finding archive versions of production tables or identifying tables that mirror a known structure.
When the table exists in multiple schemas, all instances are used as reference points.

-ExcludeViews

Excludes views from both the reference objects and the comparison results, focusing only on physical tables.
Use this when you need to find similar table structures for data migration or archiving where views aren’t relevant.

-IncludeSystemDatabases

Includes system databases (master, model, msdb, tempdb) in the similarity search.
Typically used when troubleshooting system table relationships or comparing custom objects in system databases.

-MatchPercentThreshold

Sets the minimum percentage of matching column names required to include a table pair in results.
Use values like 50 for loose matches, 80 for close structural similarity, or 95 for near-identical tables.
Zero matches are always excluded regardless of this threshold.

-EnableException

By default, when something goes wrong we try to catch it, interpret it and give you a friendly warning message.
This avoids overwhelming you with “sea of red” exceptions, but is inconvenient because it basically disables advanced scripting.
Using this switch turns this “nice by default” feature off and enables you to catch exceptions with your own try/catch.