Compare tables and columns in two schemas in MariaDB database

Query below compares columns (names) in tables between two MySQL databases (schemas). It shows columns missing in either of two schema.

Query

set @database_1 = 'database_name_1'; -- provide first database name here
set @database_2 = 'database_name_2'; -- provide second database name here
select * 
from (
        select COALESCE(c1.table_name, c2.table_name) as table_name,
               COALESCE(c1.column_name, c2.column_name) as table_column,
               c1.column_name as database1,
               c2.column_name as database2
        from
            (select table_name,
                    column_name
             from information_schema.columns c
             where c.table_schema = @database_1) c1
        right join
                 (select table_name,
                         column_name
                  from information_schema.columns c
                  where c.table_schema = @database_2) c2
        on c1.table_name = c2.table_name and c1.column_name = c2.column_name

    union

        select COALESCE(c1.table_name, c2.table_name) as table_name,
               COALESCE(c1.column_name, c2.column_name) as table_column,
               c1.column_name as schema1,
               c2.column_name as schema2
        from
            (select table_name,
                    column_name
             from information_schema.columns c
             where c.table_schema = @database_1) c1
        left join
                 (select table_name,
                         column_name
                  from information_schema.columns c
                  where c.table_schema = @database_2) c2
        on c1.table_name = c2.table_name and c1.column_name = c2.column_name
) tmp
where database1 is null
      or database2 is null
order by table_name,
         table_column;
set @database_1 = null;
set @database_2 = null;

Instruction

Replace database_name_1 and database_name_2 with names of two of your databases (schemas) (on MySQL instance) that you'd like to compare.

Columns

  • table_name - name of the table
  • table_column - name of column
  • database1 - if column exists in a table in database1 (schema) then column contains its name (repeats it from column column)
  • database2 - if column exists in a table in database2 (schema) then column contains its name (repeats it from column column)

Rows

  • One row represents one distinct name of column in specific table. Row represents column if it exist only in one schema.
  • Scope of rows: all distinct schema, table and column names in both databases.
  • Ordered by table name and column name

Sample results

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