{"id":801,"date":"2021-07-08T08:17:20","date_gmt":"2021-07-08T08:17:20","guid":{"rendered":"https:\/\/www.bearloga.space\/?page_id=801"},"modified":"2021-07-08T08:26:44","modified_gmt":"2021-07-08T08:26:44","slug":"funkczii-case-if-ifnull-coalesce","status":"publish","type":"page","link":"https:\/\/www.bearloga.space\/en\/funkczii-case-if-ifnull-coalesce\/","title":{"rendered":"\u0424\u0443\u043d\u043a\u0446\u0438\u0438 CASE, IF, IFNULL, COALESCE"},"content":{"rendered":"\n

CASE<\/h3>\n\n\n\n

\u0424\u0443\u043d\u043a\u0446\u0438\u044f CASE<\/strong> \u043f\u0440\u043e\u0432\u0435\u0440\u044f\u0435\u0442 \u0438\u0441\u0442\u0438\u043d\u043d\u043e\u0441\u0442\u044c \u043d\u0430\u0431\u043e\u0440\u0430 \u0443\u0441\u043b\u043e\u0432\u0438\u0439 \u0438 \u0432 \u0437\u0430\u0432\u0438\u0441\u0438\u043c\u043e\u0441\u0442\u0438 \u043e\u0442 \u0440\u0435\u0437\u0443\u043b\u044c\u0442\u0430\u0442\u0430 \u043f\u0440\u043e\u0432\u0435\u0440\u043a\u0438 \u043c\u043e\u0436\u0435\u0442 \u0432\u043e\u0437\u0432\u0440\u0430\u0449\u0430\u0442\u044c \u0442\u043e\u0442 \u0438\u043b\u0438 \u0438\u043d\u043e\u0439 \u0440\u0435\u0437\u0443\u043b\u044c\u0442\u0430\u0442. \u042d\u0442\u0430 \u0444\u0443\u043d\u043a\u0446\u0438\u044f \u043f\u0440\u0438\u043d\u0438\u043c\u0430\u0435\u0442 \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0443\u044e \u0444\u043e\u0440\u043c\u0443:<\/p>\n\n\n\n

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7<\/td>		CASEWHEN<\/code> \u0443\u0441\u043b\u043e\u0432\u0438\u0435_1 <\/code>
THEN<\/code> \u0440\u0435\u0437\u0443\u043b\u044c\u0442\u0430\u0442_1<\/code>
WHEN<\/code> \u0443\u0441\u043b\u043e\u0432\u0438\u0435_2 <\/code>
THEN<\/code> \u0440\u0435\u0437\u0443\u043b\u044c\u0442\u0430\u0442_2.................................<\/code>
WHEN<\/code> \u0443\u0441\u043b\u043e\u0432\u0438\u0435_N <\/code>
THEN<\/code> \u0443\u0441\u043b\u043e\u0432\u0438\u0435_N[ELSE<\/code> \u0430\u043b\u044c\u0442\u0435\u0440\u043d\u0430\u0442\u0438\u0432\u043d\u044b\u0439_\u0440\u0435\u0437\u0443\u043b\u044c\u0442\u0430\u0442]<\/code>
END<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

\u0412\u043e\u0437\u044c\u043c\u0435\u043c \u0434\u043b\u044f \u043f\u0440\u0438\u043c\u0435\u0440\u0430 \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0443\u044e \u0442\u0430\u0431\u043b\u0438\u0446\u0443 Products:<\/p>\n\n\n\n

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8<\/td>		CREATE<\/code> TABLE<\/code> Products<\/code>
(<\/code>
Id INT<\/code> AUTO_INCREMENT PRIMARY<\/code> KEY,<\/code>
ProductName VARCHAR(30) NOT<\/code> NULL<\/code>
,Manufacturer VARCHAR(20) NOT<\/code> NULL,<\/code>
ProductCount INT<\/code> DEFAULT<\/code> 0,<\/code>
Price DECIMAL<\/code> NOT<\/code> NULL<\/code>
);<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

\u0412\u044b\u043f\u043e\u043b\u043d\u0438\u043c \u0437\u0430\u043f\u0440\u043e\u0441 \u043a \u044d\u0442\u043e\u0439 \u0442\u0430\u0431\u043b\u0438\u0446\u0435 \u0438 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u0435\u043c \u0444\u0443\u043d\u043a\u0446\u0438\u044e CASE:<\/p>\n\n\n\n

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11<\/td>		SELECT<\/code> ProductName, ProductCount, <\/code>
CASE<\/code>
WHEN<\/code> ProductCount = 1 <\/code>
THEN<\/code> '\u0422\u043e\u0432\u0430\u0440 \u0437\u0430\u043a\u0430\u043d\u0447\u0438\u0432\u0430\u0435\u0442\u0441\u044f'<\/code>
WHEN<\/code> ProductCount = 2 <\/code>
THEN<\/code> '\u041c\u0430\u043b\u043e \u0442\u043e\u0432\u0430\u0440\u0430'<\/code>
WHEN<\/code> ProductCount = 3<\/code>
THEN<\/code> '\u0415\u0441\u0442\u044c \u0432 \u043d\u0430\u043b\u0438\u0447\u0438\u0438'<\/code>
ELSE<\/code> '\u041c\u043d\u043e\u0433\u043e \u0442\u043e\u0432\u0430\u0440\u0430'<\/code>
END<\/code> AS<\/code> Category<\/code>
FROM<\/code> Products;<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\"\u0424\u0443\u043d\u043a\u0446\u0438\u044f<\/figure>\n\n\n\n

\u0424\u0443\u043d\u043a\u0446\u0438\u044f IF<\/h3>\n\n\n\n

\u0424\u0443\u043d\u043a\u0446\u0438\u044f IF<\/strong> \u0432 \u0437\u0430\u0432\u0438\u0441\u0438\u043c\u043e\u0441\u0442\u0438 \u043e\u0442 \u0440\u0435\u0437\u0443\u043b\u044c\u0442\u0430\u0442\u0430 \u0443\u0441\u043b\u043e\u0432\u043d\u043e\u0433\u043e \u0432\u044b\u0440\u0430\u0436\u0435\u043d\u0438\u044f \u0432\u043e\u0437\u0432\u0440\u0430\u0449\u0430\u0435\u0442 \u043e\u0434\u043d\u043e \u0438\u0437 \u0434\u0432\u0443\u0445 \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0439. \u041e\u0431\u0449\u0430\u044f \u0444\u043e\u0440\u043c\u0430 \u0444\u0443\u043d\u043a\u0446\u0438\u0438 \u0432\u044b\u0433\u043b\u044f\u0434\u0438\u0442 \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0438\u043c \u043e\u0431\u0440\u0430\u0437\u043e\u043c:<\/p>\n\n\n\n

1<\/td>IF(\u0443\u0441\u043b\u043e\u0432\u0438\u0435, \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0435_1, \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0435_2)<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

\u0415\u0441\u043b\u0438 \u0443\u0441\u043b\u043e\u0432\u0438\u0435, \u043f\u0435\u0440\u0435\u0434\u0430\u0432\u0430\u0435\u043c\u043e\u0435 \u0432 \u043a\u0430\u0447\u0435\u0441\u0442\u0432\u0435 \u043f\u0435\u0440\u0432\u043e\u0433\u043e \u043f\u0430\u0440\u0430\u043c\u0435\u0442\u0440\u0430, \u0432\u0435\u0440\u043d\u043e, \u0442\u043e \u0432\u043e\u0437\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f \u043f\u0435\u0440\u0432\u043e\u0435 \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0435, \u0438\u043d\u0430\u0447\u0435 \u0432\u043e\u0437\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f \u0432\u0442\u043e\u0440\u043e\u0435 \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0435. \u041d\u0430\u043f\u0440\u0438\u043c\u0435\u0440:<\/p>\n\n\n\n

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3<\/td>		SELECT<\/code> ProductName, Manufacturer,<\/code>
IF(ProductCount > 3, '\u041c\u043d\u043e\u0433\u043e \u0442\u043e\u0432\u0430\u0440\u0430', '\u041c\u0430\u043b\u043e \u0442\u043e\u0432\u0430\u0440\u0430')<\/code>
FROM<\/code> Products;<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\"\u0424\u0443\u043d\u043a\u0446\u0438\u044f<\/figure>\n\n\n\n

IFNULL<\/h3>\n\n\n\n

\u0424\u0443\u043d\u043a\u0446\u0438\u044f IFNULL<\/strong> \u043f\u0440\u043e\u0432\u0435\u0440\u044f\u0435\u0442 \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0435 \u043d\u0435\u043a\u043e\u0442\u043e\u0440\u043e\u0433\u043e \u0432\u044b\u0440\u0430\u0436\u0435\u043d\u0438\u044f. \u0415\u0441\u043b\u0438 \u043e\u043d\u043e \u0440\u0430\u0432\u043d\u043e NULL, \u0442\u043e \u0444\u0443\u043d\u043a\u0446\u0438\u044f \u0432\u043e\u0437\u0432\u0440\u0430\u0449\u0430\u0435\u0442 \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0435, \u043a\u043e\u0442\u043e\u0440\u043e\u0435 \u043f\u0435\u0440\u0435\u0434\u0430\u0435\u0442\u0441\u044f \u0432 \u043a\u0430\u0447\u0435\u0441\u0442\u0432\u0435 \u0432\u0442\u043e\u0440\u043e\u0433\u043e \u043f\u0430\u0440\u0430\u043c\u0435\u0442\u0440\u0430:<\/p>\n\n\n\n

1<\/td>IFNULL(\u0432\u044b\u0440\u0430\u0436\u0435\u043d\u0438\u0435, \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0435)<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

\u041d\u0430\u043f\u0440\u0438\u043c\u0435\u0440, \u0432\u043e\u0437\u044c\u043c\u0435\u043c \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0443\u044e \u0442\u0430\u0431\u043b\u0438\u0446\u0443<\/p>\n\n\n\n

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12<\/td>		CREATE<\/code> TABLE<\/code> Clients<\/code>
(<\/code>
Id INT<\/code> AUTO_INCREMENT PRIMARY<\/code> KEY,<\/code>
FirstName VARCHAR(20) NOT<\/code> NULL,<\/code>
LastName VARCHAR(20) NOT<\/code> NULL,<\/code>
Phone VARCHAR(20) NULL,<\/code>
Email VARCHAR(20) NULL<\/code>
);<\/code> 
INSERT<\/code> INTO<\/code> Clients (FirstName, LastName, Phone, Email)<\/code>
VALUES<\/code>
('Tom', 'Smith', '+36436734', NULL),<\/code>
('Bob', 'Simpson', NULL, NULL);<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

\u0418 \u043f\u0440\u0438\u043c\u0435\u043d\u0438\u043c \u043f\u0440\u0438 \u043f\u043e\u043b\u0443\u0447\u0435\u043d\u0438\u0438 \u0434\u0430\u043d\u043d\u044b\u0445 \u0444\u0443\u043d\u043a\u0446\u0438\u044e IFNULL:<\/p>\n\n\n\n

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4<\/td>		SELECT<\/code> FirstName, LastName,<\/code>
IFNULL(Phone, '\u043d\u0435 \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0435\u043d\u043e') AS<\/code> Phone,<\/code>
IFNULL(Email, '\u043d\u0435\u0438\u0437\u0432\u0435\u0441\u0442\u043d\u043e') AS<\/code> Email<\/code>
FROM<\/code> Clients;<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
\"\u0424\u0443\u043d\u043a\u0446\u0438\u044f<\/figure>\n\n\n\n

COALESCE<\/h3>\n\n\n\n

\u0424\u0443\u043d\u043a\u0446\u0438\u044f COALESCE<\/strong> \u043f\u0440\u0438\u043d\u0438\u043c\u0430\u0435\u0442 \u0441\u043f\u0438\u0441\u043e\u043a \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0439 \u0438 \u0432\u043e\u0437\u0432\u0440\u0430\u0449\u0430\u0435\u0442 \u043f\u0435\u0440\u0432\u043e\u0435 \u0438\u0437 \u043d\u0438\u0445, \u043a\u043e\u0442\u043e\u0440\u043e\u0435 \u043d\u0435 \u0440\u0430\u0432\u043d\u043e NULL:<\/p>\n\n\n\n

1<\/td>COALESCE<\/code>(\u0432\u044b\u0440\u0430\u0436\u0435\u043d\u0438\u0435_1, \u0432\u044b\u0440\u0430\u0436\u0435\u043d\u0438\u0435_2, \u0432\u044b\u0440\u0430\u0436\u0435\u043d\u0438\u0435_N)<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

\u041d\u0430\u043f\u0440\u0438\u043c\u0435\u0440, \u0432\u044b\u0431\u0435\u0440\u0435\u043c \u0438\u0437 \u0442\u0430\u0431\u043b\u0438\u0446\u044b Clients \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u0435\u0439 \u0438 \u0432 \u043a\u043e\u043d\u0442\u0430\u043a\u0442\u0430\u0445 \u0443 \u043d\u0438\u0445 \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0438\u043c \u043b\u0438\u0431\u043e \u0442\u0435\u043b\u0435\u0444\u043e\u043d, \u043b\u0438\u0431\u043e \u044d\u043b\u0435\u043a\u0442\u0440\u043e\u043d\u043d\u044b\u0439 \u0430\u0434\u0440\u0435\u0441, \u0435\u0441\u043b\u0438 \u043e\u043d\u0438 \u043d\u0435 \u0440\u0430\u0432\u043d\u044b NULL:<\/p>\n\n\n\n

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3<\/td>		SELECT<\/code> FirstName, LastName,<\/code>
COALESCE(Phone, Email, '\u043d\u0435 \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0435\u043d\u043e') AS<\/code> Contacts<\/code>
FROM<\/code> Clients;<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

\u0422\u043e \u0435\u0441\u0442\u044c \u0432 \u0434\u0430\u043d\u043d\u043e\u043c \u0441\u043b\u0443\u0447\u0430\u0435 \u0432\u043e\u0437\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f \u0442\u0435\u043b\u0435\u0444\u043e\u043d, \u0435\u0441\u043b\u0438 \u043e\u043d \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0435\u043d. \u0415\u0441\u043b\u0438 \u043e\u043d \u043d\u0435 \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0435\u043d, \u0442\u043e \u0432\u043e\u0437\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f \u044d\u043b\u0435\u043a\u0442\u0440\u043e\u043d\u043d\u044b\u0439 \u0430\u0434\u0440\u0435\u0441. \u0415\u0441\u043b\u0438 \u0438 \u044d\u043b\u0435\u043a\u0442\u0440\u043e\u043d\u043d\u044b\u0439 \u0430\u0434\u0440\u0435\u0441 \u043d\u0435 \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0435\u043d, \u0442\u043e \u0432\u043e\u0437\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f \u0441\u0442\u0440\u043e\u043a\u0430 “\u043d\u0435 \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0435\u043d\u043e”.<\/p>\n","protected":false},"excerpt":{"rendered":"

CASE \u0424\u0443\u043d\u043a\u0446\u0438\u044f CASE \u043f\u0440\u043e\u0432\u0435\u0440\u044f\u0435\u0442 \u0438\u0441\u0442\u0438\u043d\u043d\u043e\u0441\u0442\u044c \u043d\u0430\u0431\u043e\u0440\u0430 \u0443\u0441\u043b\u043e\u0432\u0438\u0439 \u0438 \u0432 \u0437\u0430\u0432\u0438\u0441\u0438\u043c\u043e\u0441\u0442\u0438 \u043e\u0442 \u0440\u0435\u0437\u0443\u043b\u044c\u0442\u0430\u0442\u0430 \u043f\u0440\u043e\u0432\u0435\u0440\u043a\u0438 \u043c\u043e\u0436\u0435\u0442 \u0432\u043e\u0437\u0432\u0440\u0430\u0449\u0430\u0442\u044c \u0442\u043e\u0442 \u0438\u043b\u0438 \u0438\u043d\u043e\u0439 \u0440\u0435\u0437\u0443\u043b\u044c\u0442\u0430\u0442. \u042d\u0442\u0430 \u0444\u0443\u043d\u043a\u0446\u0438\u044f \u043f\u0440\u0438\u043d\u0438\u043c\u0430\u0435\u0442 […]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"categories":[75],"tags":[],"class_list":["post-801","page","type-page","status-publish","hentry","category-rukovodstvo-po-mysql"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.bearloga.space\/en\/wp-json\/wp\/v2\/pages\/801","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bearloga.space\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.bearloga.space\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.bearloga.space\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bearloga.space\/en\/wp-json\/wp\/v2\/comments?post=801"}],"version-history":[{"count":0,"href":"https:\/\/www.bearloga.space\/en\/wp-json\/wp\/v2\/pages\/801\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.bearloga.space\/en\/wp-json\/wp\/v2\/media?parent=801"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bearloga.space\/en\/wp-json\/wp\/v2\/categories?post=801"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bearloga.space\/en\/wp-json\/wp\/v2\/tags?post=801"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}