Google Big Query中的第二個子字符串

Question

我正在嘗試使用Google Big Query查找字符串中子字符串第二次出現的索引。

例如，在字符串「challcha」，「CH」的第二occurence將是在6位

我明白，這可以在使用的Oracle CHARINDEX來實現。我正試圖在Google Big Query中實現這一點。

任何幫助表示讚賞！

Answer 1

對於BigQuery的純SQL String functions

SELECT test, 
    INSTR(test, 'ch') + 1 + INSTR(SUBSTR(test, INSTR(test, 'ch') + 2), 'ch') AS pos, 
FROM 
    (SELECT 'challcha' AS test), 
    (SELECT 'chcha' AS test), 
    (SELECT 'chha' AS test) 
WHERE 
    INSTR(SUBSTR(test, INSTR(test, 'ch') + 2), 'ch') > 0 

注：INSTR是區分大小寫的，所以你可能希望把所有的下限或上限，如果您有混合的情況下

隨着BigQuery User-Defined Functions

SELECT test, pos FROM JS(
(
    SELECT test FROM 
    (SELECT 'challcha' AS test), 
    (SELECT 'chcha' AS test), 
    (SELECT 'chha' AS test) 
) , 
test, 
"[{name: 'test', type:'string'}, 
    {name: 'pos', type:'integer'} 
    ] 
", 
"function(r, emit) { 
    var search = 'ch'; 
    var pos1 = r.test.indexOf(search) + 1; 
    var pos2 = r.test.indexOf(search, pos1) + 1; 
    if (pos1 * pos2 == 0) pos2 = 0 
    emit({test: r.test, pos: pos2}); 
}" 
) 

純的BigQuery Regular expression functions

SELECT test, 
    LENGTH(REGEXP_EXTRACT(test, r'(?i)(.*?)ch')) + 3 + 
    LENGTH(REGEXP_EXTRACT(REGEXP_EXTRACT(test, r'(?i)ch(.*)'), r'(?i)(.*?)ch')) AS len, 
FROM 
    (SELECT 'ChallCha' AS test), 
    (SELECT 'abChallCha' AS test), 
    (SELECT 'chcha' AS test), 
    (SELECT 'chha' AS test)