sql-predicted-claude.yaml

# Examples of Using `CAST` and `CONVERT` in SQL with Scenarios

---

## **1. Using `CAST` to Fix Data Type Mismatch in a Join**

### Scenario
The `users` table has an `id` column of type `INT`, and the `orders` table has a `user_id` column of type `VARCHAR(10)`. You need to join these tables.

### Tables
```sql
CREATE TABLE users (
    id INT PRIMARY KEY,
    username VARCHAR(100)
);

CREATE TABLE orders (
    order_id INT PRIMARY KEY,
    user_id VARCHAR(10), -- Stored as VARCHAR but represents integers
    order_total DECIMAL(10, 2)
);

INSERT INTO users VALUES (1, 'Alice'), (2, 'Bob');
INSERT INTO orders VALUES (101, '1', 50.00), (102, '2', 100.00);
```

### Query
```sql
SELECT 
    u.username,
    o.order_total
FROM 
    users u
JOIN 
    orders o
ON 
    u.id = CAST(o.user_id AS INT);
```

### Output
| username | order_total |
|----------|-------------|
| Alice    |       50.00 |
| Bob      |      100.00 |

---

## **2. Using `CONVERT` to Format a Date in a Join**

### Scenario
The `orders` table has a `created_at` column of type `DATETIME`, and you need to display it in a readable `YYYY-MM-DD` format along with user details.

### Tables
```sql
CREATE TABLE users (
    id INT PRIMARY KEY,
    username VARCHAR(100)
);

CREATE TABLE orders (
    order_id INT PRIMARY KEY,
    user_id INT,
    created_at DATETIME
);

INSERT INTO users VALUES (1, 'Alice'), (2, 'Bob');
INSERT INTO orders VALUES (101, 1, '2025-01-01 10:00:00'), (102, 2, '2025-01-02 11:00:00');
```

### Query
```sql
SELECT 
    u.username,
    CONVERT(VARCHAR, o.created_at, 120) AS formatted_date
FROM 
    users u
JOIN 
    orders o
ON 
    u.id = o.user_id;
```

### Output
| username | formatted_date |
|----------|----------------|
| Alice    | 2025-01-01     |
| Bob      | 2025-01-02     |

---

## **3. Using `CAST` to Resolve Collation Issues**

### Scenario
The `users` and `orders` tables have `username` columns with different collations. You need to join them.

### Tables
```sql
CREATE TABLE users (
    id INT PRIMARY KEY,
    username VARCHAR(100) COLLATE SQL_Latin1_General_CP1_CI_AS
);

CREATE TABLE orders (
    order_id INT PRIMARY KEY,
    username VARCHAR(100) COLLATE Latin1_General_CI_AS,
    order_total DECIMAL(10, 2)
);

INSERT INTO users VALUES (1, 'Alice'), (2, 'Bob');
INSERT INTO orders VALUES (101, 'Alice', 50.00), (102, 'Bob', 100.00);
```

### Query
```sql
SELECT 
    u.username,
    o.order_total
FROM 
    users u
JOIN 
    orders o
ON 
    u.username = o.username COLLATE SQL_Latin1_General_CP1_CI_AS;
```

### Output
| username | order_total |
|----------|-------------|
| Alice    |       50.00 |
| Bob      |      100.00 |

---

## **4. Using `CONVERT` to Format Numeric Data in a Join**

### Scenario
You want to join the `users` and `orders` tables and display the `order_total` column as a formatted string.

### Tables
```sql
CREATE TABLE users (
    id INT PRIMARY KEY,
    username VARCHAR(100)
);

CREATE TABLE orders (
    order_id INT PRIMARY KEY,
    user_id INT,
    order_total DECIMAL(10, 2)
);

INSERT INTO users VALUES (1, 'Alice'), (2, 'Bob');
INSERT INTO orders VALUES (101, 1, 50.00), (102, 2, 100.50);
```

### Query
```sql
SELECT 
    u.username,
    CONVERT(VARCHAR(50), o.order_total) AS formatted_total
FROM 
    users u
JOIN 
    orders o
ON 
    u.id = o.user_id;
```

### Output
| username | formatted_total |
|----------|-----------------|
| Alice    | 50.00           |
| Bob      | 100.50          |

---

## **5. Combining `CAST` and `CONVERT` in a Query**

### Scenario
The `users` table has `id` as `INT`, and the `orders` table has `user_id` as `VARCHAR`. Additionally, you need the `order_total` column as a string.

### Tables
(Same as above)

### Query
```sql
SELECT 
    u.username,
    CAST(o.user_id AS INT) AS user_id_cast,
    CONVERT(VARCHAR, o.order_total, 1) AS formatted_order_total
FROM 
    users u
JOIN 
    orders o
ON 
    u.id = CAST(o.user_id AS INT);
```

### Output
| username | user_id_cast | formatted_order_total |
|----------|--------------|-----------------------|
| Alice    |            1 | 50.00                |
| Bob      |            2 | 100.50               |