sql - up table set number2 = number where number != "" and set number, number2 = $number where number = "";; -

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is possible?

update table set number2 = number number != "" , set number, number2 = $number number="";

or need do

update table set number2 = number number != ""; update table set number = $number, number2 = number number = "";

i them 2 "separate" statements , not worry trying find clever solution (which clever imnsho).

you'll see quoted word "separate" above since decent dbms provide transactional support make 2 of statements one, in terms of atomicity (the in acid).

in other words, like:

start transaction; update table set number2 = number number != ""; update table set number = $number, number2 = number number = ""; commit transaction;

this invariably faster (assuming number indexed) clever solution using per-row functions case, if , on, since 2 fast passes better 1 slow pass :-)


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