comparing two tables in sql code example

Example 1: sql compare tables for differences

-- Find the different tables and columns between DB_NBR_1 and DB_NBR_2
-- (just replace DB_NBR_1 and DB_NBR_2)
select isnull(db1.table_name, db2.table_name) as [table],
       isnull(db1.column_name, db2.column_name) as [column],
       db1.column_name as scripts_col_name
      ,db1.column_type as scripts_col_type
       ,db1.column_precision as scripts_col_precision

      ,db2.column_name as liquid_col_name
      ,db2.column_type as liquid_col_type
      ,db2.column_precision as liquid_col_precision
from
(select schema_name(tab.schema_id) + '.' + tab.name as table_name, 
       col.name as column_name
      ,y.name as column_type
      ,y.precision as column_precision
   from [DB_NBR_1].sys.tables as tab
        inner join [DB_NBR_1].sys.columns as col
            on tab.object_id = col.object_id
         JOIN sys.types y ON y.user_type_id = col.user_type_id
         ) db1
full outer join
(select schema_name(tab.schema_id) + '.' + tab.name as table_name, 
       col.name as column_name
      ,y.name as column_type
      ,y.precision as column_precision
   from [DB_NBR_2].sys.tables as tab
        inner join [DB_NBR_2].sys.columns as col
            on tab.object_id = col.object_id
         JOIN sys.types y ON y.user_type_id = col.user_type_id
         ) db2
on db1.table_name = db2.table_name
and db1.column_name = db2.column_name
where (db1.column_name is null or db2.column_name is null)
order by 1, 2, 3

Example 2: sql difference between tables

-- Oracle

-- Example
SELECT * 
FROM Table1 -- the table containing extra records
  MINUS
  SELECT * 
  FROM Table2;

-- Syntax 
SELECT * 
FROM <table-1> -- the table containing extra records
  MINUS
  SELECT * 
  FROM <table-2>;

Example 3: sql compare data from two tables

select * from tableA
minus
select * from tableB