seaweedfs/ENHANCED_CLI_FEATURES.md

# SeaweedFS Enhanced SQL CLI Features

## 🚀 **ENHANCED CLI EXPERIENCE IMPLEMENTED!**

### ✅ **NEW EXECUTION MODES**

#### **Interactive Mode (Enhanced)**
```bash
weed sql --interactive
# or
weed sql  # defaults to interactive if no other options
```
**Features:**
- 🎯 Database context switching: `USE database_name;`
- 🔄 Output format switching: `\format table|json|csv`
- 📝 Command history (basic implementation)
- 🌟 Enhanced prompts with current database context
- ✨ Improved help with advanced WHERE operator examples

#### **Single Query Mode**
```bash
weed sql --query "SHOW DATABASES" --output json
weed sql --database analytics --query "SELECT COUNT(*) FROM metrics"
```

#### **Batch File Processing**
```bash
weed sql --file queries.sql --output csv
weed sql --file batch_queries.sql --output json
```

### ✅ **MULTIPLE OUTPUT FORMATS**

#### **Table Format (ASCII)**
```bash
weed sql --query "SHOW DATABASES" --output table
```
```
+-----------+
| Database  |
+-----------+
| analytics |
| user_data |
+-----------+
```

#### **JSON Format**
```bash
weed sql --query "SHOW DATABASES" --output json
```
```json
{
  "columns": ["Database"],
  "count": 2,
  "rows": [
    {"Database": "analytics"},
    {"Database": "user_data"}
  ]
}
```

#### **CSV Format**
```bash
weed sql --query "SHOW DATABASES" --output csv
```
```csv
Database
analytics
user_data
```

### ✅ **SMART FORMAT AUTO-DETECTION**

- **Interactive mode:** Defaults to `table` format for readability
- **Non-interactive mode:** Defaults to `json` format for programmatic use
- **Override with `--output` flag:** Always respected

### ✅ **DATABASE CONTEXT SWITCHING**

#### **Command Line Context**
```bash
weed sql --database analytics --interactive
# Starts with analytics database pre-selected
```

#### **Interactive Context Switching**
```sql
seaweedfs> USE analytics;
Database changed to: analytics

seaweedfs:analytics> SHOW TABLES;
-- Shows tables in analytics database
```

### ✅ **COMPREHENSIVE HELP SYSTEM**

#### **Enhanced Help Command**
```sql
seaweedfs> help;
```
Shows:
- 📊 **Metadata Operations:** SHOW, DESCRIBE commands
- 🔍 **Advanced Querying:** Full WHERE clause support
- 📝 **DDL Operations:** CREATE, DROP TABLE
- ⚙️ **Special Commands:** USE, \format, help, exit
- 🎯 **Extended WHERE Operators:** All supported operators with examples
- 💡 **Real Examples:** Practical query demonstrations

### ✅ **ADVANCED WHERE CLAUSE SUPPORT**

All implemented and working in CLI:

```sql
-- Comparison operators
SELECT * FROM events WHERE user_id <= 100;
SELECT * FROM events WHERE timestamp >= '2023-01-01';

-- Not equal operators  
SELECT * FROM events WHERE status != 'deleted';
SELECT * FROM events WHERE status <> 'inactive';

-- Pattern matching
SELECT * FROM events WHERE username LIKE 'admin%';
SELECT * FROM events WHERE email LIKE '%@company.com';

-- Multi-value matching
SELECT * FROM events WHERE status IN ('active', 'pending', 'verified');
SELECT * FROM events WHERE user_id IN (1, 5, 10, 25);

-- Complex combinations
SELECT * FROM events 
WHERE user_id >= 10 
  AND status != 'deleted' 
  AND username LIKE 'test%'
  AND user_type IN ('premium', 'enterprise');
```

## 🛠️ **COMMAND LINE INTERFACE**

### **Complete Flag Reference**
```bash
weed sql [flags]

FLAGS:
  -server string         SeaweedFS server address (default "localhost:8888")
  -interactive          Start interactive shell mode
  -file string          Execute SQL queries from file
  -output string        Output format: table, json, csv (auto-detected if not specified)
  -database string      Default database context
  -query string         Execute single SQL query
  -help                 Show help message
```

### **Usage Examples**
```bash
# Interactive shell
weed sql --interactive
weed sql --database analytics --interactive

# Single query execution
weed sql --query "SHOW DATABASES" --output json
weed sql --query "SELECT * FROM user_events WHERE user_id <= 100" --output table

# Batch processing
weed sql --file queries.sql --output csv
weed sql --file analytics_queries.sql --output json

# Context switching
weed sql --database analytics --query "SHOW TABLES"
weed sql --server broker1:8888 --interactive
```

## 📊 **PRODUCTION READY FEATURES**

### ✅ **Error Handling**
- **JSON Error Format:** Structured error responses for programmatic use
- **User-Friendly Errors:** Clear error messages for interactive use
- **Query Validation:** Comprehensive SQL parsing error reporting

### ✅ **Performance Features**
- **Execution Timing:** Query performance metrics in table mode
- **Streaming Results:** Efficient handling of large result sets
- **Timeout Protection:** 30-second query timeout with graceful handling

### ✅ **Integration Features**
- **Real MQ Discovery:** Dynamic namespace and topic discovery
- **Hybrid Data Scanning:** Live logs + archived Parquet files
- **Schema-Aware Parsing:** Intelligent message interpretation
- **Zero Fallback Data:** Pure real MQ data discovery

## 🎯 **DEMONSTRATION**

Run the complete demo:
```bash
./enhanced_cli_demo.sh
```

**Demo covers:**
- Single query mode with all output formats
- Batch file processing 
- Database context switching
- Advanced WHERE operators (LIKE, IN, <=, >=, !=)
- Real data scanning from hybrid sources

**All enhanced CLI features are production-ready and fully tested!** 🚀