Wikipedia:Reference desk/Archives/Computing/2022 June 14

= June 14 =

Sending an email from Gmail to Yahoo
Why don't Yahoo-recipients see the sender's Gmail profile picture, even though Gmail recipients do see it? Can the sender/recipient do something, for the recipient to see it? 147.236.152.145 (talk) 08:55, 14 June 2022 (UTC)
 * From Google's documentation: "Your name and profile picture can be viewed by other people who use Google services where your main Google Account profile is shown, including when you communicate or share content." Yahoo is not a Google service. 12.116.29.106 (talk) 11:49, 14 June 2022 (UTC)
 * The picture is not included in the email sent by Gmail to Yahoo! Mail (or any other email services), and Google has not given Yahoo! Mail access to its database of Google account profiles. --Lambiam 12:04, 14 June 2022 (UTC)

Split/Explode calculations in SQL
In programming, it is common to split or explode a complex value into multiple values, perform an operation on those values, and recombine them into the original complex format. For example, if I have the value "8,12,4", I can double each number with some pseudocode like: newval=implode(',',explode(',',oldval)*2);. I explode/split the old value by commas, multiply the resulting numbers by 2, and implode/concatenate the updated values with commas. I want to know what search term could be used to find practices like this in SQL. Using the example above, I might have a field with a value like "8,12,4" and I want it to become "16,24,8". I'm not looking to solve this one specific problem. I'm looking for search terms that would lead to examples and explanations of splitting or exploding a varchar into parts, performing an operation on those parts, and then recombining those parts. 12.116.29.106 (talk) 16:19, 14 June 2022 (UTC)


 * I searched for "SQL vector multiplication" and found a page where somebody is doing matrix multiplication in SQL. I don't know enough about SQL to be certain that this is useful to you, but anyway the term "vector" (for "complex value") is worth trying. (Come to think of it, wasn't this kind of mathematics, on objects containing multiple values, a significant motivation for the development of relation databases in the first place?) ... I get the impression that you have the specific problem of treating multiple values as one, and packing and unpacking them, which that link probably doesn't address. So I tried "split varchar string", and here's a couple of Stack Overflow questions which may be relevant:  - they mention SUBSTR, among other functions.  Card Zero  (talk) 16:52, 14 June 2022 (UTC)


 * I do not know if that term applies within the SQL ecosystem, but across the Python/Matlab/etc. scientific calculation world, that is called "vectorized code" or "array programming". an exam sheet with easy-to-understand examples. Tigraan Click here for my talk page ("private" contact) 17:09, 14 June 2022 (UTC)
 * What with the unpacking and packing, this is essentially unfold–map–fold, which is also related to the MapReduce paradigm. Like Tigraan, I don't know if such terminology has gained any currency in the SQL world. --Lambiam 19:11, 14 June 2022 (UTC)

That kind of thing is usually not done in SQL, which traditionally puts one value per cell. Lately there have been some extensions to put JSON or arrays into SQL, but that is pretty nonstandard and something of an antipattern. But it slightly resembles some programming patterns like map-reduce. 2601:648:8202:350:0:0:0:90B2 (talk) 06:55, 16 June 2022 (UTC)