Added script to find tables with matching columns by name

Author: thomasjbarrett82

Scripts/Compare_Tables_With_Matching_Columns.sql

@@ -0,0 +1,129 @@
+/*
+<documentation>
+ <summary>Find all matching column names between tables. Useful for exploring databases with implied relationships but no foreign keys.</summary>
+ <returns>1 data set: temp table #results.</returns>
+ <issues>No</issues>
+ <author>Tom Barrett</author>
+ <created>2022-08-27</created>
+ <modified>2022-08-27 by Tom Barrett</modified>
+ <version>1.0</version>
+</documentation>
+*/
+
+SET NOCOUNT ON;
+
+/* create staging objects */
+IF object_id('tempdb..#tablesToQuery') IS NOT NULL
+BEGIN
+DROP TABLE #tablesToQuery
+END
+
+CREATE TABLE #tablesToQuery (
+DatabaseName NVARCHAR(1000)
+, SchemaName NVARCHAR(1000)
+, TableName NVARCHAR(1000)
+, IsProcessed BIT DEFAULT 0
+)
+GO
+
+IF object_id('tempdb..#results') IS NOT NULL
+BEGIN
+DROP TABLE #results
+END
+
+CREATE TABLE #results (
+DatabaseName NVARCHAR(1000)
+, ColumnName NVARCHAR(1000)
+, Table1 NVARCHAR(1000)
+, Table2 NVARCHAR(1000)
+)
+GO
+
+/* get list of tables */
+INSERT INTO #tablesToQuery (
+DatabaseName
+, SchemaName
+, TableName
+)
+SELECT TABLE_CATALOG
+, TABLE_SCHEMA
+, TABLE_NAME
+FROM INFORMATION_SCHEMA.TABLES
+ORDER BY TABLE_CATALOG
+, TABLE_SCHEMA
+, TABLE_NAME
+GO
+
+/* loop through tables and get matching columns by name */
+DECLARE @x INT = 1;
+DECLARE @table NVARCHAR(1000);
+
+WHILE @x <= (
+SELECT count('dracula')
+FROM #tablesToQuery
+WHERE IsProcessed = 0
+)
+BEGIN
+/* get next table*/
+SELECT TOP 1 @table = TableName
+FROM #tablesToQuery
+WHERE IsProcessed = 0;
+
+/* insert into #results any tables + columns that match */
+WITH cte
+AS (
+SELECT TABLE_CATALOG
+, TABLE_SCHEMA
+, TABLE_NAME
+, COLUMN_NAME
+FROM INFORMATION_SCHEMA.COLUMNS
+)
+INSERT INTO #results
+SELECT cte1.TABLE_CATALOG
+, cte1.COLUMN_NAME
+, CONCAT (
+cte1.TABLE_SCHEMA
+, '.'
+, cte1.TABLE_NAME
+)
+, CONCAT (
+cte2.TABLE_SCHEMA
+, '.'
+, cte2.TABLE_NAME
+)
+FROM cte AS cte1
+JOIN cte AS cte2 ON cte1.TABLE_CATALOG = cte2.TABLE_CATALOG
+AND cte1.TABLE_SCHEMA collate Latin1_general_CI_AI = cte2.TABLE_SCHEMA collate Latin1_general_CI_AI /* remove this line to search different schemas*/
+AND cte1.TABLE_NAME collate Latin1_general_CI_AI <> cte2.TABLE_NAME collate Latin1_general_CI_AI
+AND cte1.COLUMN_NAME collate Latin1_general_CI_AI = cte2.COLUMN_NAME collate Latin1_general_CI_AI
+WHERE cte1.TABLE_NAME = @table
+/* add any other irrelevant or metadata columns to exclude */
+AND cte1.COLUMN_NAME collate Latin1_general_CI_AI NOT IN (
+'ID'
+, 'ACTIVE'
+, 'CREATEDBY'
+, 'ETC.'
+) 
+
+UPDATE #tablesToQuery
+SET IsProcessed = 1
+WHERE TableName = @table;
+END
+
+/* return results */
+SELECT *
+FROM #results
+/* uncomment this line to search results for a specific table */
+/* WHERE Table1 = 'Schema.Table' */
+ORDER BY ColumnName
+, Table1
+, Table2
+GO
+
+/* clean up */
+DROP TABLE #results
+GO
+
+DROP TABLE #tablesToQuery
+GO
+