Solutions:

1.
CREATE TABLE sales_optimized (
  sale_id VARCHAR(50),
  customer_id VARCHAR(50),
  sale_date DATE,
  amount DECIMAL(10,2),
  product_id VARCHAR(50)
)
DISTKEY (customer_id)
SORTKEY (sale_date);

2.
COPY products
FROM 's3://my-bucket/products/data/'
IAM_ROLE 'arn:aws:iam::123456789012:role/RedshiftCopyRole'
FORMAT AS PARQUET;

3.
UNLOAD ('SELECT * FROM customers')
TO 's3://my-bucket/customers/export/'
IAM_ROLE 'arn:aws:iam::123456789012:role/RedshiftUnloadRole'
FORMAT AS PARQUET
PARALLEL OFF;

4.
CREATE TABLE dim_categories (
  category_id INT,
  category_name VARCHAR(100),
  parent_category_id INT
)
DISTSTYLE ALL
SORTKEY (category_id);

5.
-- Fact table
CREATE TABLE fact_sales (
  sale_id VARCHAR(50),
  customer_id VARCHAR(50),
  product_id VARCHAR(50),
  sale_date DATE,
  amount DECIMAL(10,2)
)
DISTKEY (customer_id)
SORTKEY (sale_date);

-- Dimension table
CREATE TABLE dim_products (
  product_id VARCHAR(50),
  product_name VARCHAR(100),
  category_id INT,
  price DECIMAL(10,2)
)
DISTSTYLE ALL
SORTKEY (product_id);

6.
COPY sales
FROM 's3://my-bucket/sales/data/'
IAM_ROLE 'arn:aws:iam::123456789012:role/RedshiftCopyRole'
FORMAT AS CSV
STATUPDATE ON
MAXERROR 100
COMPUPDATE ON;

7.
-- For even distribution across slices
CREATE TABLE large_sales (
  sale_id VARCHAR(50),
  customer_id VARCHAR(50),
  sale_date DATE,
  amount DECIMAL(10,2)
)
DISTSTYLE EVEN
SORTKEY (sale_date);

-- OR for join optimization
CREATE TABLE large_sales (
  sale_id VARCHAR(50),
  customer_id VARCHAR(50),
  sale_date DATE,
  amount DECIMAL(10,2)
)
DISTKEY (customer_id)
SORTKEY (sale_date);

8.
CREATE EXTERNAL SCHEMA spectrum_schema
FROM DATA CATALOG
DATABASE 'external_db'
IAM_ROLE 'arn:aws:iam::123456789012:role/RedshiftSpectrumRole';

SELECT * FROM spectrum_schema.sales_data
WHERE sale_date >= '2023-01-01';

9.
CREATE TABLE sales_interleaved (
  sale_id VARCHAR(50),
  customer_id VARCHAR(50),
  product_id VARCHAR(50),
  sale_date DATE,
  amount DECIMAL(10,2)
)
DISTKEY (customer_id)
INTERLEAVED SORTKEY (sale_date, product_id, customer_id);

10.
COPY products
FROM 's3://my-bucket/products/data/'
IAM_ROLE 'arn:aws:iam::123456789012:role/RedshiftCopyRole'
FORMAT AS PARQUET
COMPUPDATE ON;

11.
CREATE TABLE auto_distributed (
  id INT,
  name VARCHAR(100),
  created_date DATE,
  value DECIMAL(10,2)
)
DISTSTYLE AUTO
SORTKEY (created_date);

12.
-- Both tables distributed on the same key for efficient joins
CREATE TABLE orders (
  order_id VARCHAR(50),
  customer_id VARCHAR(50),
  order_date DATE,
  amount DECIMAL(10,2)
)
DISTKEY (customer_id)
SORTKEY (order_date);

CREATE TABLE customers (
  customer_id VARCHAR(50),
  customer_name VARCHAR(100),
  region VARCHAR(50)
)
DISTKEY (customer_id)
SORTKEY (customer_id);

13.
COPY sales
FROM 's3://my-bucket/sales/manifest'
IAM_ROLE 'arn:aws:iam::123456789012:role/RedshiftCopyRole'
FORMAT AS CSV
MANIFEST;

14.
CREATE MATERIALIZED VIEW mv_daily_sales
AS
SELECT 
  sale_date,
  product_id,
  SUM(amount) as daily_sales,
  COUNT(*) as transaction_count
FROM sales
GROUP BY sale_date, product_id;

15.
CREATE WORKLOAD GROUP etl_group
WITH (
  CONCURRENCY_SCALING_MODE = 'AUTO',
  QUERY_QUEUE_COUNT = 2
);

CREATE WORKLOAD GROUP reporting_group
WITH (
  CONCURRENCY_SCALING_MODE = 'AUTO',
  QUERY_QUEUE_COUNT = 4,
  QUERY_TIMEOUT = 300000
);

CREATE WORKLOAD MAPPING
FOR USER etl_user
TO WORKLOAD GROUP etl_group;

CREATE WORKLOAD MAPPING
FOR USER reporting_user
TO WORKLOAD GROUP reporting_group;