indexing

问题 I read all the relevant duplicated questions/answers and I found this to be the most relevant answer: INSERT IGNORE INTO temp(MAILING_ID,REPORT_ID) SELECT DISTINCT MAILING_ID,REPORT_IDFROM table_1 ; The problem is that I want to remove duplicates by col1 and col2, but also want to include to the insert all the other fields of table_1. I tried to add all the relevant columns this way: INSERT IGNORE INTO temp(M_ID,MAILING_ID,REPORT_ID, MAILING_NAME,VISIBILITY,EXPORTED) SELECT DISTINCT M_ID

问题 I have two string variables: $names = "Sean Connery,George Lazenby,Roger Moore,Timothy Dalton,Pierce,Brosnan,Daniel Craig"; $movies = "Dr. No/On Her Majesty's Secret Service/Live and Let Die/The Living Daylights/GoldenEye/Casino Royal"; I need to convert these two strings into an associative array with $names as the index and $movies as the values . How would I do this? 回答1: I would do it with something like this: $array = array_combine(explode(',',$names),explode('/',$movies)); 来源： https:/

问题 I have two string variables: $names = "Sean Connery,George Lazenby,Roger Moore,Timothy Dalton,Pierce,Brosnan,Daniel Craig"; $movies = "Dr. No/On Her Majesty's Secret Service/Live and Let Die/The Living Daylights/GoldenEye/Casino Royal"; I need to convert these two strings into an associative array with $names as the index and $movies as the values . How would I do this? 回答1: I would do it with something like this: $array = array_combine(explode(',',$names),explode('/',$movies)); 来源： https:/

问题 [1, 2, 3].indexOf(3) => 2 [1, 2, NaN].indexOf(NaN) => -1 [1, NaN, 3].indexOf(NaN) => -1 回答1: You can use Array.prototype.findIndex method to find out the index of NaN in an array let index = [1,3,4,'hello',NaN,3].findIndex(Number.isNaN) console.log(index) You can use Array.prototype.includes to check if NaN is present in an array or not. It won't give you the index though !! It will return a boolean value. If NaN is present true will be returned, otherwise false will be returned let

问题 [1, 2, 3].indexOf(3) => 2 [1, 2, NaN].indexOf(NaN) => -1 [1, NaN, 3].indexOf(NaN) => -1 回答1: You can use Array.prototype.findIndex method to find out the index of NaN in an array let index = [1,3,4,'hello',NaN,3].findIndex(Number.isNaN) console.log(index) You can use Array.prototype.includes to check if NaN is present in an array or not. It won't give you the index though !! It will return a boolean value. If NaN is present true will be returned, otherwise false will be returned let

来源： https://stackoverflow.com/questions/3379292/is-an-index-needed-for-a-primary-key-in-sqlite

来源： https://stackoverflow.com/questions/3379292/is-an-index-needed-for-a-primary-key-in-sqlite

来源： https://stackoverflow.com/questions/64542167/included-columns-are-used-in-seek-operator

来源： https://stackoverflow.com/questions/64542167/included-columns-are-used-in-seek-operator

来源： https://stackoverflow.com/questions/62155325/how-to-index-coordinate-data-according-to-a-grid-in-r