On Fri, Feb 14, 2014 at 2:33 PM, Max Vlasov <max.vla...@gmail.com> wrote: > Hi, > > Some time ago when there was no "instr" functions, I looked at Mysql help > pages and implemented a user function "locate" as the one that allows > searching starting a particular position in the string. With two parameters > form it was just identical to "instr" only the order of parameters was > reversed. As I see, the latest sqlite has only "instr". > > It's not a big deal, but I noticed that "locate" with three parameters > becomes convenient for CTE recursive queries since it allows search > sequentially in the string. For example, a little bulky at last, but I > managed to do "comma-list to dataset" query > > I suppose implementing "locate" and doing "instr" as a call to "locate" > would cost the developers probably no more than a hundred of bytes for the > final binary
Parsing fields is also done with substring_index in MySQL and having both locate and substring_index would be useful for MySQL compatibility. Parsing fields created using group_concat is one particular example. One related item is that in MySQL group_concat can specify the order of rows to be concatenated as well as a number of other aspects not currently available in SQLite. -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.com _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
