RQE - Restful Query Expression

RQE (Readable Query Expression) is a lightweight and powerful query expression parser for Go that translates human-readable query strings into structured SQL queries with placeholders and arguments.

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🚀 Features

✅ SQL Query Generation – Converts human-friendly filters into SQL
✅ SQL Supported Operations – EQ, LT, GT, GTE, IN, BETWEEN, LTE, NE... etc ✅ Supports Logical Operators – AND, ORand logic nesting. Complicated AND | Ors ✅ Custom Column Validation – Prevents invalid column names and sql injection ✅ Multi-Value Expressions – Supports arrays inside IN clauses
✅ Error Handling with Context – Returns structured errors with line numbers

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📦 Installation

Install RQE via go get:

go get github.com/baderkha/rqe

Import it in your Go project:

import "github.com/baderkha/rqe"

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🛠 Usage

Basic Example

package main

import (
	"fmt"
	"github.com/baderkha/rqe"
)

func main() {
	filter := `name eq "John" and age gte 25 or (city eq "New York" and status in ["active", "pending"])`

	validateCol := func(col string) bool {
		return map[string]bool{"name": true, "age": true, "city": true, "status": true}[col]
	}

	query, err := rqe.Parse(filter, validateCol)
	if err != nil {
		fmt.Println("Error:", err)
		return
	}

	fmt.Println("Formatted SQL:\n", query.SQL)
	fmt.Println("Arguments:", query.Args)
}

🔹 Output

name = ?
AND age >= ?
OR (
  city = ?
  AND status IN ( ?, ? )
)

["John", 25, "New York", "active", "pending"]

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🏗 Query Syntax

Operator	Meaning	Example	SQL Equivalent
eq	Equal	age eq 30	age = ?
ne	Not Equal	status ne "banned"	status <> ?
lt	Less Than	price lt 100	price < ?
lte	Less or Equal	score lte 50	score <= ?
gt	Greater Than	rating gt 4.5	rating > ?
gte	Greater or Equal	salary gte 5000	salary >= ?
in	Multiple Values	color in ["red","blue"]	color IN (?, ?)
between	Range Check	age between [18 65]	age BETWEEN ? AND ?

Logical Operators

• AND – name eq "Alice" and age gte 21
• OR – status eq "active" or status eq "pending"
• Parentheses – ( age gte 18 and age lte 65 )

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🔥 Error Handling

RQE provides structured errors with line and column numbers.

query, err := rqe.Parse(`name eq "John" and age eq and city eq "New York"`, validateCol)
if err != nil {
	if parseErr, ok := err.(rqe.ParseError); ok {
		line, col := parseErr.Position()
		fmt.Printf("Error: %s at line %d, column %d\n", parseErr.Error(), line, col)
	} else {
		fmt.Println("Unknown error:", err)
	}
}

🔹 Example Error Output

Error: expected a valid value for column 'age' at line 1, column 20

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💡 Contributing

We welcome contributions! If you find a bug or want to add new features, feel free to open an issue or a pull request.

1. Fork the repository
2. Create a new branch (git checkout -b feature-branch)
3. Commit changes (git commit -m "Added new feature")
4. Push to GitHub (git push origin feature-branch)
5. Create a Pull Request

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📄 License

This project is licensed under the MIT License. See LICENSE for details.

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📢 Contact & Support

• GitHub: github.com/baderkha/rqe
• Issues: github.com/baderkha/rqe/issues

Enjoy using RQE! 🎉🚀