Update sqlquery.md

adds missing datatype (i.e. Varchar) to the database field 'Name' of the Class 'Player'
Update DropdownField.php

An error in the example (missing comma) spotted by michaelcslweb
Merge pull request #3166 from phillprice/patch-2

Update DropdownField.php
Merge pull request #3165 from sanjaymundhra/patch-9

Update sqlquery.md
Remove redundant ternary expression

Replace it with casting to a boolean
Merge pull request #3174 from camspiers/patch-1

Remove redundant ternary expression
Update modeladmin.md

DataList is immutable, so need to assign.