mysql - Update and select count at the same time taken too much time -

-

i have mysql statement:

update student_performance_cache spc set badges = (select count(ub.mb_no) user_badges ub ub.mb_no=spc.student_id)

i got problems query taken time when data become larger. how can improve mysql statement , make faster?


Comments

Post a Comment

Popular posts from this blog

python - argument must be rect style object - Pygame -

-
disclaimer: know other people on site have had error it's been in different contexts , fixes don't seem work here. hey stackoverflow, i've been making sideways space invaders game, ship follows mouse's y position stays on left, , clicking shoots bullet. enemies spawn randomly right , fly left, , objects removed once each side of screen. works fine, when tried implement collision detection see when shot hits enemy, error: typeerror: argument must rect style object. it points line "return hitbox.colliderect(target.rect)". try , work out causing made 'print' lines below see 'target.rect' (and whether proper rect object), , seemed same style shot's own rect, i'm lost why colliderect doesn't accept it. i've annotated pretty everything, sorry if it's insult intelligence should make things easier. class causes problems: class gameobject: def __init__(self, image, height, speed): self.speed = speed self.image...
Read more

c++ - Qt setGeometry: Unable to set geometry -

-
why? setgeometry: unable set geometry 22x22+320+145 on qwidgetwindow/'widgetclasswindow'. resulting geometry: 116x22+320+145 (frame: 8, 30, 8, 8, custom margin: 0, 0, 0, 0, minimum size: 22x22, maximum size: 16777215x16777215). the project is: project.pro qt += core gui greaterthan(qt_major_version, 4): qt += widgets target = untitled5 template = app sources += main.cpp\ widget.cpp headers += widget.h widget.h #ifndef widget_h #define widget_h #include <qwidget> class widget : public qwidget { q_object public: explicit widget(qwidget *parent = 0); ~widget(); private: }; #endif // widget_h widget.cpp #include "widget.h" #include <qvboxlayout> widget::widget(qwidget *parent) : qwidget(parent) { qvboxlayout *vlayout = new qvboxlayout(this); } widget::~widget() { } main.cpp #include "widget.h" #include <qapplication> int main(int argc, char *argv[]) { qapplication a...
Read more

php - Zend Framework / Skeleton-Application / Composer install issue -

-
i trying create zend framework application using skeleton in netbeans. when run composer install, following error message: "c:\php\php.exe" "c:\composer\composer.phar" "--ansi" "--no-interaction" "update" "--dev" using deprecated option "dev". dev packages installed default now. loading composer repositories package information updating dependencies (including require-dev) requirements not resolved installable set of packages. problem 1 - package requires php >=5.5 php version (5.4.42) not satisfy requirement. problem 2 - installation request zendframework/zendframework 2.5.1 -> satisfiable zendframework/zendframework[2.5.1]. - zendframework/zendframework 2.5.1 requires php >=5.5 -> php version (5.4.42) not satisfy requirement. done. apparently, zend framework only needs php 5.3+ contradicts above. need use php 5.4. my composer.json following: { "name": ...
Read more