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Dgraph DQL Tour

Var Blocks

Value variables - min and max

We’ve just looked at variables that stored uid results from query blocks. Value variables store the values against which they match.

Value variables work differently to query variables. Value variables are context dependent - in fact, they are a map from UID to value and we can exploit this when reading and filtering value variables. The value from a value variable is extracted with val(<variable-name>).

At the point of definition, because the context is within the appropriate UID, value variables act like the corresponding value. In the enclosing block, value variables are the UID to value map and must be aggregated.

Aggregations over value variables aren’t dependent on an index - there’s no need for indexing, the values have already been found in the query.

min and max can be applied to int, float, string, bool, and date types.

Dgraph DQL Tour

An interactive tutorial with real queries and real results, designed to run on Chrome on your machine.

Modules

. GraphQL Introduction . GraphQL Basic Features . GraphQL Schema . GraphQL Search . GraphQL Data and More Data . DQL Introduction . DQL Basic Features . DQL Schema . DQL Data and More Data . DQL Query Blocks and Variables . DQL Search

DQL Query Blocks and Variables

This module shows you how to build more powerful queries with multiple query blocks and query variables.

Module Breakdown

5.1. Multiple Named Query Blocks 5.2. Query Variables 5.3. Query Variables in a child block 5.4. Query Variables in another query block I 5.5. Query Variables in another query block II 5.6. Exercise: Query Variables linking queries 5.7. Value variables - min and max 5.8. Exercise : Value variables - sum and avg 5.9. Value variables: filtering and ordering 5.10. Value variables: math functions 5.11. Exercise : Latest Movies 5.12. GroupBy 5.13. Congratulations!
Endpoint: /query
Dgraph: http://localhost:8080
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Response

5.7 Value variables - min and max