Today on 8.3.6 Multiple-Column Indexes I learned about the hash index technique:
SELECT * FROM tbl_name
AND col1=val1 AND col2=val2;
As they say: “As an alternative to a composite index, you can introduce a column that is “hashed” based on information from other columns. If this column is short, reasonably unique, and indexed, it might be faster than a “wide” index on many columns. In MySQL, it is very easy to use this extra column.”
I don’t use spreadsheets much, and when I do it’s usually LibreOffice Calc, but today I came across Index and Match which described the INDEX and MATCH spreadsheet functions and that looked handy so I thought I might make a note!
Using AngularJS I was getting the error “Error: Duplicates in a repeater are not allowed.” I found a comment on StackOverflow that suggested instead of:
<div ng-repeat="row in [1,1,1]">
<div ng-repeat="row in [1,1,1] track by $index">
A magical ‘track by $index’!