Record Left Anti Join Tool
Return left records without an exact typed-scalar right-key match, retaining absent left-key records and source indexes.
Description
Return left records without an exact typed-scalar right-key match, retaining absent left-key records and source indexes.
A left anti-join keeps left-side records without a matching right-side key. It can identify unmatched imports or records that need further mapping.
When to use this tool
Return left records without an exact typed-scalar right-key match, retaining absent left-key records and source indexes.
- Prepare the supplied leftRecordsJson, rightRecordsJson, leftKey, rightKey fields for this operation.
- Compare the complete example with the representation used by your own input before carrying the result into another step.
How to use the tool and how it works
- Enter leftRecordsJson, rightRecordsJson, leftKey, rightKey. Use the exact text syntax, units and index conventions explained below.
- Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
- Read result.records, result.sourceIndexes. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Build a set of present rightKey scalar values, then retain each left record whose leftKey is absent or has no typed match. Return retained records and original left indexes.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| leftRecordsJson | JSON text, entered as one text field. The decoded structure is illustrated below; it is not a separate file. | Text |
| rightRecordsJson | JSON text, entered as one text field. The decoded structure is illustrated below; it is not a separate file. | Text |
| leftKey | left key. | Text; at most 8,192 UTF-16 code units, subject to the grammar above |
| rightKey | right key. | Text; at most 8,192 UTF-16 code units, subject to the grammar above |
For the JSON text fields, the following decoded structures show the example records before they are serialized into input strings. Keep field names, list nesting and value types as shown.
[
{
"field": "leftRecordsJson",
"decoded": [
{
"id": 1
},
{
"id": 2
},
{}
]
},
{
"field": "rightRecordsJson",
"decoded": [
{
"id": 1
}
]
}
]| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.records | The records list in the ordering and representation described above. |
| result.sourceIndexes | Original zero-based source positions, under the ordering described above. |
{
"input": {
"leftRecordsJson": "[{\"id\":1},{\"id\":2},{}]",
"rightRecordsJson": "[{\"id\":1}]",
"leftKey": "id",
"rightKey": "id"
},
"output": {
"result": {
"records": [
{
"id": 2
},
{}
],
"sourceIndexes": [
1,
2
]
}
}
}Limitations and assumptions
- Missing left keys are included. Key comparisons distinguish scalar types and reject containers; right duplicates do not multiply the output and input order is preserved.
- Decoded JSON is bounded to 20,000 nodes and 32 nesting levels; record arrays have at most 128 records. Parsed number values use JavaScript floating point rather than arbitrary-precision decimal arithmetic.
- Every declared top-level field is required and unexpected fields are rejected. Numeric inputs must be finite; ordinary text fields are bounded to 8,192 UTF-16 code units, with tighter operation-specific limits where stated.
- Ordinary string lists have at most 128 entries of at most 128 code units each; numeric lists and matrices have separate bounded size checks. Nonfinite results and excessively large serialized outputs are rejected.
- Indexes are zero-based and spans have an exclusive end unless explicitly stated otherwise. A valid false, null or empty-list result is distinct from malformed input.
Alternative or Complementary methods
For document-wide requirements, combine these structural inventories with an explicit JSON Schema. Preserve the distinction between missing properties and null values, and between numbers and numeric-looking strings when building joins or indexes.
References
Similar or alternative tools
- Record Equijoin Cardinality Counter
Count exact typed-scalar equijoin pairs with full duplicate multiplicity; absent members do not join, explicit null values can join.
- Record Array Unique Key Indexer
Build a unique typed-scalar record index as entries; numeric and string keys remain distinct, missing and duplicate keys fail.