docs(samples): add query script

[pmakani]

Thank you for opening a Pull Request! Before submitting your PR, there are a few things you can do to make sure it goes smoothly:

• Make sure to open an issue as a bug/issue before writing your code! That way we can discuss the change, evaluate designs, and agree on the general idea
• Ensure the tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

[codecov]

Codecov Report

Merging #605 into master will decrease coverage by 0.04%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #605      +/-   ##
============================================
- Coverage     81.49%   81.45%   -0.05%     
+ Complexity     1226     1225       -1     
============================================
  Files            77       77              
  Lines          6220     6200      -20     
  Branches        691      677      -14     
============================================
- Hits           5069     5050      -19     
+ Misses          792      791       -1     
  Partials        359      359              

Impacted Files	Coverage Δ	Complexity Δ
...com/google/cloud/bigquery/StandardSQLDataType.java	73.68% <0.00%> (-1.32%)	7.00% <0.00%> (ø%)
...m/google/cloud/bigquery/StandardSQLStructType.java	84.61% <0.00%> (-1.10%)	5.00% <0.00%> (ø%)
...gle/cloud/bigquery/MaterializedViewDefinition.java	70.00% <0.00%> (-0.97%)	6.00% <0.00%> (ø%)
...ava/com/google/cloud/bigquery/RoutineArgument.java	90.47% <0.00%> (-0.44%)	5.00% <0.00%> (ø%)
...va/com/google/cloud/bigquery/StandardSQLField.java	90.47% <0.00%> (-0.44%)	7.00% <0.00%> (ø%)
...java/com/google/cloud/bigquery/ViewDefinition.java	87.09% <0.00%> (-0.41%)	11.00% <0.00%> (ø%)
...google/cloud/bigquery/ExternalTableDefinition.java	57.69% <0.00%> (-0.41%)	19.00% <0.00%> (ø%)
...y/src/main/java/com/google/cloud/bigquery/Job.java	86.13% <0.00%> (-0.20%)	31.00% <0.00%> (-1.00%)
...om/google/cloud/bigquery/BigtableColumnFamily.java	95.83% <0.00%> (-0.17%)	5.00% <0.00%> (ø%)
...google/cloud/bigquery/StandardTableDefinition.java	93.24% <0.00%> (-0.10%)	16.00% <0.00%> (ø%)
... and 8 more

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