描述

動(dòng)態(tài)參數(shù)類似的數(shù)據(jù)庫(kù)中的PrepareStatement。用戶可以在SQL中設(shè)置placeholder（?表示），同時(shí)傳遞placeholder對(duì)應(yīng)的值。引擎內(nèi)部會(huì)自動(dòng)替換。

動(dòng)態(tài)參數(shù)主要用于提高Cache命中率，對(duì)于查詢模式固定的場(chǎng)景性能提升明顯。

注意動(dòng)態(tài)參數(shù)只能替換值，不支持關(guān)鍵字或字段替換。

示例

示例1

SELECT i1, cast(? as bigint) FROM t1 WHERE (i2 > 5 AND d3 < 10.1) OR s5 = ?

為了替換掉SQL中的動(dòng)態(tài)參數(shù)（也就是"?"）,具體如下：

 dynamic_params:[[10, "str5"]]

示例2

SELECT
    price,
    title,
    compute(
        longitude,
        latitude,
        city_id,
        CAST(? AS double),
        CAST(? AS double),
        CAST(1 AS bigint)
    ) AS distance
FROM
    store,
    unnest(store.sub_table)
WHERE
    MATCHINDEX('shop', ?)
    AND QUERY(name, ?) 

dynamic_params:[[119.98844256998, 
                36.776817017143, 
                "excellect", 
                "水果 OR 西瓜"]]