Crafting SQL Queries Effectively in Go

Concatenating strings with values in text SQL queries can be a bit tricky in Go. Unlike Python, Go's string formatting syntax behaves differently, leading to common errors like the one encountered here.

Tuple Syntax Error

The initial code snippet tries to use a Python-style tuple, which is not supported in Go. This results in a syntax error:

query := fmt.Sprintf(`SELECT column_name FROM table_name
        WHERE column1_name = %d AND column2_name = %d`,
        (val1, val2))

Mismatched Types

Attempting to cast the tuple elements as strings also fails due to a type mismatch:

query := fmt.Sprintf(`SELECT column_name FROM table_name
        WHERE column1_name = %d AND column2_name = %d`,
        val1, val2)

Avoid Operator Mismatch

Casting the parameters as strings and concatenating them with the operator %s would work but is not recommended. This approach introduces the risk of operator mismatch:

query := fmt.Sprintf(`SELECT column_name FROM table_name
        WHERE column1_name = %s AND column2_name = %s`,
        strconv.Itoa(val1), val2)

The Go Solution

To correctly write a text SQL query with value concatenation in Go, use fmt.Sprintf as follows:

query := fmt.Sprintf(`SELECT column_name FROM table_name
        WHERE column1_name = %d AND column2_name = %s`,
        val1, val2)

This syntax avoids injection vulnerabilities and ensures proper type conversion.

Injection Prevention

To prevent SQL injection attacks, always use prepared statements or provide escape characters for user-supplied inputs.