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How to compare two databases using T-SQL?
The T-SQL code generates 2 tables in different databases. The table names are the same, but the table in database dbtest02 contains an extra row as shown below: Let’s look at ways we can compare these tables using different methods. With the LEFT JOIN we can compare values of specific columns that are not common between two tables.
How to find out content differences between 2 SQL Server?
EXCEPT command takes two SELECT statements and returns the rows that are returned by the first SELECT statement (left) and not by second (right) SELECT statement. P.S: The schema for both the tables returned by SELECT statement must match.
How to get the differences between two tables?
IF you have tables A and B, both with colum C, here are the records, which are present in table A but not in B: To get all the differences with a single query, a full join must be used, like this:
How to return difference between two SQL queries?
FROM ( SELECT * FROM Table2 EXCEPT SELECT * FROM Table1 ) AS T2 ; Simple variation on @erikkallen answer that shows which table the row is present in: All queries combined using a UNION, INTERSECT or EXCEPT operator must have an equal number of expressions in their target lists.
When do you need to compare two tables?
This is when the need to compare data in two tables appears. Before comparing data in two tables, you need to make sure that the schemas of the compared tables are either the same or acceptably different. By acceptably different, we mean a difference in the definition of two tables, whereby data can be compared correctly.
How to compare employee tables in two databases?
We can see here that despite the differences between the definitions of the Employee tables in two databases, the table columns that we need for comparison are identical in data type. This means that the difference in the schemas of the Employee tables is acceptable. That is, we can compare the data in these two tables.
Are there two tables in the same database?
The T-SQL code generates 2 tables in different databases. The table names are the same, but the table in database dbtest02 contains an extra row as shown below: Let’s look at ways we can compare these tables using different methods.
What happens if the values in two columns are the same?
If the values in the columns that need to compare are the same, the COUNT (*) returns 2, otherwise the COUNT (*) returns 1. If values in the columns involved in the comparison are identical, no row returns.