In MongoDB, there isn't a built-in LPAD function like in traditional SQL databases. However, you can achieve similar functionality using the aggregation framework and a combination of string manipulation operators. Here's how you can pad a string to the left in MongoDB:
Suppose you have a collection employees with documents containing an employee_name field, and you want to pad each employee_name to a length of 15 characters with asterisks (*) to the left:
db.employees.aggregate([
{
$addFields: {
padded_name: {
$concat: [
{
$substrCP: [
"***************",
0,
{ $subtract: [15, { $strLenCP: "$employee_name" }] }
]
},
"$employee_name"
]
}
}
}
])
In this aggregation:
- $strLenCP calculates the length of the original employee_name.
- $subtract calculates the number of asterisks (*) needed to pad the string to a total length of 15 characters.
- $substrCP extracts a substring of asterisks (*) based on the calculated padding length.
- $concat concatenates the generated padding string with the original employee_name.
This aggregation will produce a new field padded_name in each document, containing the employee_name padded to a length of 15 characters with asterisks (*) to the left. Adjust the length and padding character as needed for your specific requirements.
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