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- $strcasecmp (aggregation)
$strcasecmp (aggregation)¶
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Definition¶
- $strcasecmp¶
Performs case-insensitive comparison of two strings. Returns
- 1 if first string is “greater than” the second string.
- 0 if the two strings are equal.
- -1 if the first string is “less than” the second string.
$strcasecmp has the following syntax:
{ $strcasecmp: [ <expression1>, <expression2> ] }
The arguments can be any valid expression as long as they resolve to strings. For more information on expressions, see Expressions.
Behavior¶
$strcasecmp only has a well-defined behavior for strings of ASCII characters.
For a case sensitive comparison, see $cmp.
Example¶
Consider a inventory collection with the following documents:
{ "_id" : 1, "item" : "ABC1", quarter: "13Q1", "description" : "product 1" }
{ "_id" : 2, "item" : "ABC2", quarter: "13Q4", "description" : "product 2" }
{ "_id" : 3, "item" : "XYZ1", quarter: "14Q2", "description" : null }
The following operation uses the $strcasecmp operator to perform case-insensitive comparison of the quarter field value to the string "13q4":
db.inventory.aggregate(
[
{
$project:
{
item: 1,
comparisonResult: { $strcasecmp: [ "$quarter", "13q4" ] }
}
}
]
)
The operation returns the following results:
{ "_id" : 1, "item" : "ABC1", "comparisonResult" : -1 }
{ "_id" : 2, "item" : "ABC2", "comparisonResult" : 0 }
{ "_id" : 3, "item" : "XYZ1", "comparisonResult" : 1 }