mysql_database_schema.sql

SELECT 
    cols.TABLE_SCHEMA as 'database',
    cols.TABLE_NAME as 'table',
    cols.COLUMN_NAME as 'column',
    cols.DATA_TYPE AS 'data_type',
    cols.COLUMN_TYPE AS 'type',
    COALESCE(cols.COLUMN_DEFAULT, cols.extra) AS 'default',
    (
        CASE WHEN COLUMN_KEY='PRI'
        THEN 'YES'
        ELSE 'NO'
        END
    ) AS 'is_primary',
    (
        CASE WHEN COLUMN_KEY='MUL'
        THEN 'YES'
        ELSE 'NO'
        END
    ) AS 'is_primary',
    cols.IS_NULLABLE AS 'is_nullable',
    constraints.CONSTRAINT_NAME AS 'constraint',
    constraints.REFERENCED_TABLE_SCHEMA AS 'referenced_database',
    constraints.REFERENCED_TABLE_NAME  AS 'referenced_table',
    constraints.REFERENCED_COLUMN_NAME AS 'referenced_column'
  FROM INFORMATION_SCHEMA.COLUMNS cols
    LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE constraints
        ON cols.TABLE_SCHEMA = constraints.TABLE_SCHEMA
            AND cols.TABLE_NAME = constraints.TABLE_NAME
            AND cols.COLUMN_NAME = constraints.COLUMN_NAME
  WHERE
    cols.TABLE_SCHEMA != 'mysql'
    AND cols.TABLE_SCHEMA != 'performance_schema'
    AND cols.TABLE_SCHEMA != 'information_schema'
    AND cols.TABLE_SCHEMA != 'sys';

psql_database_schema.sql

SELECT 
    cols.TABLE_CATALOG AS "database",
    cols.TABLE_SCHEMA AS "schema",
    cols.TABLE_NAME AS "table",
    cols.COLUMN_NAME AS "column",
    cols.DATA_TYPE AS "data_type",
    cols.COLUMN_DEFAULT AS "default",
    cols.IS_NULLABLE AS "is_nullable",
    COALESCE(constraints.is_foreign, 'NO') AS "is_foreign",
    COALESCE(constraints.is_primary, 'NO') AS "is_primary",
    constraints.constraint AS "constraint",
    constraints.referenced_database AS "referenced_database",
    constraints.referenced_schema AS "referenced_schema",
    constraints.referenced_table  AS "referenced_table",
    constraints.referenced_column AS "referenced_column"
  FROM INFORMATION_SCHEMA.COLUMNS cols
    LEFT JOIN (
        SELECT
            cols.TABLE_CATALOG AS "referenced_database",
            cols.TABLE_SCHEMA AS "referenced_schema",
            cols.TABLE_NAME AS "referenced_table",
            cols.COLUMN_NAME AS "referenced_column",
            refs.table_catalog AS "from_database",
            refs.table_schema AS "from_schema",
            refs.table_name AS "from_table",
            refs.column_name AS "from_column",
            refs.CONSTRAINT_NAME AS "constraint",
            'YES' AS "is_foreign",
            NULL AS "is_primary"
        FROM INFORMATION_SCHEMA.COLUMNS cols
            INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE refs
                ON cols.TABLE_CATALOG=refs.constraint_catalog
                AND cols.TABLE_SCHEMA=refs.constraint_schema
                AND cols.table_name=refs.table_name
                AND cols.ordinal_position=refs.position_in_unique_constraint
        UNION
        SELECT
            NULL AS "referenced_database",
            NULL AS "referenced_schema",
            NULL AS "referenced_table",
            NULL AS "referenced_column",
            refs.table_catalog AS "from_database",
            refs.table_schema AS "from_schema",
            refs.table_name AS "from_table",
            refs.column_name AS "from_column",
            refs.CONSTRAINT_NAME AS "constraint",
            NULL AS "is_foreign",
            'YES' AS "is_primary"
        FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE refs
        WHERE refs.position_in_unique_constraint IS NULL
    ) constraints
        ON cols.TABLE_CATALOG=constraints.from_database
            AND cols.TABLE_SCHEMA=constraints.from_schema
            AND cols.table_name=constraints.from_table
            AND cols.column_name=constraints.from_column
WHERE
    cols.TABLE_SCHEMA != 'pg_catalog'
    AND cols.TABLE_SCHEMA != 'information_schema'
ORDER BY cols.TABLE_CATALOG, cols.TABLE_SCHEMA, cols.TABLE_NAME, cols.COLUMN_NAME;