matchPhrasePrefix
语法
matchPhrasePrefix(textCol, phrase, prefix)
参数
textCol 待查询的列,即 PKEY 存储引擎中设置了文本索引的列。
phrase STRING 类型标量,用于指定待查询的短语。
prefix STRING 类型标量,用于指定待查询的前缀。
详情
该函数用于 SQL 语句的 WHERE 子句,针对 PKEY 存储引擎中设置文本索引的列进行文本匹配,若包含特定短语,且短语后是某一特定前缀的单词,则该行匹配成功。返回所有匹配成功的行。
例子
// 构造数据
stringColumn = ["There are some apples and oranges.","Mike likes apples.","Alice likes oranges.","Mike gives Alice an apple.","Alice gives Mike an orange.","John likes peaches, so he does not give them to anyone.","Mike, can you give me some apples?","Alice, can you give me some oranges?","Mike traded an orange for an apple with Alice."]
t = table([1,1,1,2,2,2,3,3,3] as id1, [1,2,3,1,2,3,1,2,3] as id2, stringColumn as remark)
if(existsDatabase("dfs://textDB")) dropDatabase("dfs://textDB")
db = database(directory="dfs://textDB", partitionType=VALUE, partitionScheme=[1,2,3], engine="PKEY")
pt = createPartitionedTable(dbHandle=db, table=t, tableName="pt", partitionColumns="id1",primaryKey=`id1`id2,indexes={"remark":"textindex(parser=english, full=false, lowercase=true, stem=true)"})
pt.tableInsert(t)
// 匹配包含单词 give,且 give 后为 mi 前缀单词的行
select * from pt where matchPhrasePrefix(remark,"give","mi")
id1 |
id2 |
remark |
---|---|---|
2 | 2 | Alice gives Mike an orange. |