I have several tables in Amazon RedShift that follow the pattern of several dimension columns and a pair of metric name/value columns.
DimensionA DimensionB MetricName MetricValue
---------- ---------- ---------- -----------
dimA1 dimB1 m1 v11
dimA1 dimB2 m1 v12
dimA1 dimB2 m2 v21
dimA2 dimB2 m1 v13
dimA3 dimB1 m2 v22
I am looking for a good way to unwind/pivot the data into a form of one row per each unique dimension set, e.g.:
DimensionA DimensionB m1 m2
---------- ---------- --- ---
dimA1 dimB1 v11
dimA1 dimB2 v12 v21
dimA2 dimB2 v13
dimA3 dimB1 v22
What is a good pattern for generating queries that would perform this unwinding?
Amazon RedShift is based on ParAccel and supports PostgreSQL 8.0.2, which does not have crosstab, unnest, pivot or unpivot.