diff --git a/doc/lab2design.txt b/doc/lab2design.txt
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+CS122 Assignment 2 - SQL Translation and Joins - Design Document
+================================================================
+
+Fill in answers for all questions based on your team's work on Assignment 2.
+
+A: Simple Planner
+------------------
+
+A1. Without going into the details of how you handle grouping and
+ aggregation or joins, list the general sequence of steps that your
+ planner's makePlan() method follows to translate a SQL query into
+ an execution plan.
+
+A2. Does your planner try to simplify plans in specific circumstances,
+ e.g. when a "trivial project" is used (i.e. "SELECT * FROM ...") in
+ your planner? Briefly enumerate all simplifications and optimizations
+ your planner employs.
+
+A3. Describe how you generate the execution-plan fragment for the query's
+ FromClause. Make sure to touch on what you do in the three cases your
+ planner is expected to handle - tables, subqueries in the FROM clause,
+ and joins.
+
+A4. Describe how you implemented support for grouping and aggregation.
+ Be sure to note any variations from the approach outlined in class,
+ if there are any.
+
+B: Nested-Loop Join
+--------------------
+
+B1. The join algorithm stated in class is really only suitable for
+ materialized evaluation, where the entire result is generated by the
+ algorithm. It is completely unsuitable for pipelined evaluation,
+ where results are generated row by row.
+
+ Summarize how your implementation works for inner joins, using
+ pseudocode to show how rows are considered and returned as the
+ algorithm executes, and what state must be saved so that the
+ operation can resume at the appropriate place when the next row
+ must be returned.
+
+B2. What tweaks did you need to introduce into the implementation for
+ left outer joins? Keep your answer brief, but please also be specific.
+
+B3. Enumerate your nested-loop join test cases, following this form:
+
+ * <test-case class name>.<test function>
+ <brief one-sentence description of what the test exercises>
+
+C: Extra Credit [OPTIONAL]
+---------------------------
+
+If you implemented any extra-credit tasks for this assignment, describe
+them here. The description should be like this, with stuff in "<>" replaced.
+(The value i starts at 1 and increments...)
+
+D<i>: <one-line description>
+
+ <brief summary of what you did, including the specific classes that
+ we should look at for your implementation>
+
+ <brief summary of test-cases that demonstrate/exercise your extra work>
+
+E: Feedback [OPTIONAL]
+-----------------------
+
+WE NEED YOUR FEEDBACK! Thoughtful and constructive input will help us to
+improve future versions of the course. These questions are OPTIONAL, and
+your answers will not affect your grade in any way (including if you hate
+everything about the assignment and databases in general, or Donnie and/or
+the TAs in particular). Feel free to answer as many or as few of them as
+you wish.
+
+E1. What parts of the assignment were most time-consuming? Why?
+
+E2. Did you find any parts of the assignment particularly instructive?
+ Correspondingly, did any parts feel like unnecessary busy-work?
+
+E3. Did you particularly enjoy any parts of the assignment? Were there
+ any parts that you particularly disliked?
+
+E4. Were there any critical details that you wish had been provided with the
+ assignment, that we should consider including in subsequent versions of
+ the assignment?
+
+E5. Do you have any other suggestions for how future versions of the
+ assignment can be improved?
+
diff --git a/doc/lab2info.txt b/doc/lab2info.txt
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+CS122 Assignment 2 - SQL Translation and Joins - Logistics
+==========================================================
+
+Please completely fill out this document so that we know who participated on
+the assignment, any late extensions received, and how much time the assignment
+took for your team. Thank you!
+
+L1. List your team name and the people who worked on this assignment.
+
+ <team name>
+
+ <name>
+ <name>
+ ...
+
+L2. Specify the tag and commit-hash of the Git commit you are submitting for
+ your assignment. (You can list the hashes of all tags with the command
+ "git show-ref --tags".)
+
+ Tag: <tag>
+ Commit hash: <hash>
+
+L3. Specify how many late tokens you are applying to this assignment, if any.
+ Similarly, if your team received an extension from Donnie then please
+ indicate how many days extension you received. You may leave this blank
+ if it is not relevant to this submission.
+
+ <tokens / extension>
+
+L4. For each teammate, briefly describe what parts of the assignment each
+ teammate focused on, along with the total hours spent on the assignment.
+
+
diff --git a/src/main/java/edu/caltech/nanodb/queryeval/InvalidSQLException.java b/src/main/java/edu/caltech/nanodb/queryeval/InvalidSQLException.java
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+++ b/src/main/java/edu/caltech/nanodb/queryeval/InvalidSQLException.java
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+package edu.caltech.nanodb.queryeval;
+
+
+import edu.caltech.nanodb.server.NanoDBException;
+
+
+/**
+ * This exception is used to signal when a SQL query contains a semantic error
+ * that prevents its evaluation. For example, an expression like
+ * "<tt>MAX(AVG(a))</tt>" is invalid and cannot be evaluated.
+ */
+public class InvalidSQLException extends NanoDBException {
+ public InvalidSQLException() {
+ super();
+ }
+
+ public InvalidSQLException(String msg) {
+ super(msg);
+ }
+
+ public InvalidSQLException(Throwable cause) {
+ super(cause);
+ }
+
+ public InvalidSQLException(String msg, Throwable cause) {
+ super(msg, cause);
+ }
+}