Adjacency Search

[jcuenod]

With a sliding window function, we should be able to do "adjacency" searches in parabible. This will not force an order of wids (not a sequence search), but it is a useful first step. The relevant "WINDOW" function docs for clickhouse are pasted below. First, though, here's a mocked up query that does something useful:

select * from (
SELECT
    groupArray(rid) OVER w1 AS rids,
    groupArray(wid) OVER w1 AS wids,
    groupArray(text) OVER w1 AS words,
    groupArray(lexeme) OVER w1 AS lexemes,
    groupArrayIf(lexeme, lexeme='ἐκκλησία') OVER w1 AS w1,
    groupArrayIf(lexeme, lexeme='παροικέω') OVER w1 AS w2
FROM word_features
WINDOW
    w1 AS (PARTITION BY module_id ORDER BY wid ASC Rows BETWEEN 2 PRECEDING AND 2 FOLLOWING)
)
where length(w1) > 0 and length(w2) > 0
LIMIT 10

-- first_value and last_value respect the frame
SELECT
    groupArray(value) OVER w1 AS frame_values_1,
    first_value(value) OVER w1 AS first_value_1,
    last_value(value) OVER w1 AS last_value_1,
    groupArray(value) OVER w2 AS frame_values_2,
    first_value(value) OVER w2 AS first_value_2,
    last_value(value) OVER w2 AS last_value_2
FROM wf_frame
WINDOW
    w1 AS (PARTITION BY part_key ORDER BY order ASC),
    w2 AS (PARTITION BY part_key ORDER BY order ASC Rows BETWEEN 1 PRECEDING AND CURRENT ROW)
ORDER BY
    part_key ASC,
    value ASC;
┌─frame_values_1─┬─first_value_1─┬─last_value_1─┬─frame_values_2─┬─first_value_2─┬─last_value_2─┐
│ [1]            │             1 │            1 │ [1]            │             1 │            1 │
│ [1,2]          │             1 │            2 │ [1,2]          │             1 │            2 │
│ [1,2,3]        │             1 │            3 │ [2,3]          │             2 │            3 │
│ [1,2,3,4]      │             1 │            4 │ [3,4]          │             3 │            4 │
│ [1,2,3,4,5]    │             1 │            5 │ [4,5]          │             4 │            5 │
└────────────────┴───────────────┴──────────────┴────────────────┴───────────────┴──────────────┘

-- second value within the frame
SELECT
    groupArray(value) OVER w1 AS frame_values_1,
    nth_value(value, 2) OVER w1 AS second_value
FROM wf_frame
WINDOW w1 AS (PARTITION BY part_key ORDER BY order ASC Rows BETWEEN 3 PRECEDING AND CURRENT ROW)
ORDER BY
    part_key ASC,
    value ASC
┌─frame_values_1─┬─second_value─┐
│ [1]            │            0 │
│ [1,2]          │            2 │
│ [1,2,3]        │            2 │
│ [1,2,3,4]      │            2 │
│ [2,3,4,5]      │            3 │
└────────────────┴──────────────┘

-- second value within the frame + Null for missing values
SELECT
    groupArray(value) OVER w1 AS frame_values_1,
    nth_value(toNullable(value), 2) OVER w1 AS second_value
FROM wf_frame
WINDOW w1 AS (PARTITION BY part_key ORDER BY order ASC Rows BETWEEN 3 PRECEDING AND CURRENT ROW)
ORDER BY
    part_key ASC,
    value ASC
┌─frame_values_1─┬─second_value─┐
│ [1]            │         ᴺᵁᴸᴸ │
│ [1,2]          │            2 │
│ [1,2,3]        │            2 │
│ [1,2,3,4]      │            2 │
│ [2,3,4,5]      │            3 │
└────────────────┴──────────────┘
```sql