# Query: travel-sample
# Flags: WordMatch RegExp
# Including: ./docs-server
# Excluding: *.html,*.json

N1QL subquery pages

modules/n1ql/pages/n1ql-language-reference/correlated-subqueries.adoc:
   62: FROM `travel-sample`  t1
   64:                        FROM `travel-sample` t2
   91: * FROM clause of the subquery in xref:n1ql-language-reference/subqueries.adoc#Q7[Q7] is an independent keyspace identifier `pass:c[`travel-sample`]` and hence the correlation with parent query is established explicitly using the USE KEYS clause through the referential attribute `t1.airlineid`.
   94: * Similarly, the subquery in xref:n1ql-language-reference/subqueries.adoc#Q6A[Q6A] has an independent keyspace identifier `pass:c[`travel-sample`]` in FROM clause, but the correlation is self-referencing to the same document.
   99: Note that, in `pass:c[`travel-sample`]` keyspace data model, the `"route"` documents refer the `"airline"` documents using the attribute `airlineid`.
  126: FROM `travel-sample` route
  127:       JOIN `travel-sample` airline

modules/n1ql/pages/n1ql-language-reference/subqueries.adoc:
   33: FROM `travel-sample` t1
   36:                   FROM `travel-sample`
   56:       FROM `travel-sample` WHERE type = "airport"
   77:                   FROM `travel-sample` WHERE type = "airport"
  105: For example, in the above query <<Q1,Q1>>, the keyspace identifier `pass:c[`travel-sample`]` in the outer query is not considered a variable for the subquery.
  116: FROM `travel-sample` t1
  135: The reference to `t2` in the subquery is actually referring to the same document from `pass:c[`travel-sample`]` that is being processed as `t1` in the outer query.
  143: FROM `travel-sample` t1
  172: In the following equivalent queries, explicit alias `t` of `pass:c[`travel-sample`]` or LET variable `x` is treated as an expression and hence a nested path like `t.geo.lat` is allowed in the subquery FROM clause.
  178: SELECT count(*) FROM `travel-sample` t
  186: SELECT count(*) FROM `travel-sample` t
  194: SELECT count(*) FROM `travel-sample` t
  203: SELECT count(*) FROM `travel-sample` t
  212: For example, the following example <<Q6,Q6>> has no explicit alias for `pass:c[`travel-sample`]`.
  213: So the `pass:c[`travel-sample`]` used in subquery FROM clause is considered keyspace identifier, but not an expression.
  214: That makes the subquery non-correlated by the FROM clause, and the subquery returns all documents from keyspace `pass:c[`travel-sample`]`.
  221:                      FROM `travel-sample` t1))
  222: FROM `travel-sample` LIMIT 4;
  240: FROM `travel-sample` t;
  258:                      FROM `travel-sample`))
  259: FROM `travel-sample`;
  264:     "msg": "Duplicate subquery alias travel-sample",
  265:     "query_from_user": "SELECT array_length((SELECT RAW t1.geo.alt \nFROM `travel-sample` ))\nFROM `travel-sample`;"
  272: In the following example Q6C, the `from-term` has nested path `pass:c[`travel-sample`.geo]` as expression where `pass:c[`travel-sample`]` is referring to the implicit alias of the keyspace in the parent query.
  280:                      FROM `travel-sample`.geo t1))
  281: FROM `travel-sample`
  299: SELECT * FROM `travel-sample` t1
  354: FROM (SELECT geo from `travel-sample`
  393: The following two queries show valid and invalid examples with `travel-sample` data set.
  401: FROM `travel-sample` t1
  404:       FROM `travel-sample`.geo t2)[0] > 4000;
  408:     "msg": "Ambiguous reference to field travel-sample.",
  409:     "query_from_user": "SELECT t1.city, t1.geo.alt\nFROM `travel-sample` t1\nWHERE t1.type = \"airport\" AND \n(SELECT RAW t2.alt \n FROM `travel-sample`.geo t2)[0] > 4000;"
  419: FROM `travel-sample` t1
  435: The following example demonstrates the power of using nested path expressions in xref:n1ql-language-reference/correlated-subqueries.adoc[correlated subqueries] over the array subdocument `pass:c[`travel-sample`.reviews]`.
  443: FROM `travel-sample` AS t
  469: FROM   `travel-sample` AS t
  471:                      FROM `travel-sample` tmp

modules/n1ql/pages/n1ql-language-reference/subquery-examples.adoc:
   15: FROM   `travel-sample` AS t
   45:              FROM `travel-sample`.schedule s
   48: FROM `travel-sample`
   92: FROM  `travel-sample`
   94:                            FROM `travel-sample`.schedule as s WHERE s.day = 1)[0]  > 4
  121: FROM   `travel-sample` AS t
  153: MERGE INTO `travel-sample` t USING [{"id":"21728"},{"id":"21730"}] source
  178: SELECT count(*) FROM `travel-sample` t
  190:                      FROM `travel-sample` t1))
  191: FROM `travel-sample` LIMIT 4;
  208: FROM `travel-sample` t;
  223: Update `travel-sample`  t1 set airportname_dup = "high_altitude_" || airportname
  225:                                            FROM `travel-sample` t2
  236: UPDATE  `travel-sample`  t1
  252: UPDATE `travel-sample` t1
  268: INSERT INTO `travel-sample`  t1 (KEY _k, VALUE _v)
  270: FROM `travel-sample` t2
  281: DELETE FROM `travel-sample` t