{"id":60575,"date":"2024-10-13T04:00:18","date_gmt":"2024-10-12T20:00:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/60575\/"},"modified":"2024-10-13T04:00:18","modified_gmt":"2024-10-12T20:00:18","slug":"db2%e6%b5%81%e7%a8%8b%e6%8e%a7%e5%88%b6%e5%ad%90%e5%8f%a5%e4%b8%80%e8%a6%bd","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/60575\/","title":{"rendered":"DB2\u6d41\u7a0b\u63a7\u5236\u5b50\u53e5\u4e00\u89bd"},"content":{"rendered":"

DB2\u6d41\u7a0b\u63a7\u5236\u5b50\u53e5\u4e00\u89bd<\/h1>\n

\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u6d41\u7a0b\u63a7\u5236\u5b50\u53e5\u662f\u7528\u4f86\u63a7\u5236\u7a0b\u5f0f\u57f7\u884c\u6d41\u7a0b\u7684\u91cd\u8981\u5de5\u5177\u3002IBM\u7684DB2\u8cc7\u6599\u5eab\u7cfb\u7d71\u63d0\u4f9b\u4e86\u591a\u7a2e\u6d41\u7a0b\u63a7\u5236\u5b50\u53e5\uff0c\u9019\u4e9b\u5b50\u53e5\u80fd\u5920\u5e6b\u52a9\u958b\u767c\u8005\u5728SQL\u7a0b\u5f0f\u4e2d\u5be6\u73fe\u66f4\u8907\u96dc\u7684\u908f\u8f2f\u3002\u672c\u6587\u5c07\u5c0dDB2\u4e2d\u7684\u4e3b\u8981\u6d41\u7a0b\u63a7\u5236\u5b50\u53e5\u9032\u884c\u8a73\u7d30\u4ecb\u7d39\u3002<\/p>\n

1. IF-THEN-ELSE\u5b50\u53e5<\/h2>\n

IF-THEN-ELSE\u5b50\u53e5\u662f\u6700\u5e38\u7528\u7684\u6d41\u7a0b\u63a7\u5236\u7d50\u69cb\u4e4b\u4e00\u3002\u5b83\u5141\u8a31\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u57f7\u884c\u4e0d\u540c\u7684\u7a0b\u5f0f\u78bc\u584a\u3002\u4ee5\u4e0b\u662f\u5176\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n

\nIF condition THEN\n    -- \u57f7\u884c\u7684\u7a0b\u5f0f\u78bc\nELSE\n    -- \u5176\u4ed6\u7a0b\u5f0f\u78bc\nEND IF;\n<\/code><\/pre>\n
\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u9700\u8981\u6839\u64da\u54e1\u5de5\u7684\u85aa\u6c34\u4f86\u6c7a\u5b9a\u662f\u5426\u7d66\u4e88\u734e\u91d1\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n
\nIF salary > 50000 THEN\n    bonus = 1000;\nELSE\n    bonus = 500;\nEND IF;\n<\/code><\/pre>\n
2. CASE\u5b50\u53e5<\/h2>\n
CASE\u5b50\u53e5\u63d0\u4f9b\u4e86\u4e00\u7a2e\u66f4\u9748\u6d3b\u7684\u65b9\u5f0f\u4f86\u8655\u7406\u591a\u500b\u689d\u4ef6\u3002\u5b83\u53ef\u4ee5\u7528\u65bc\u9078\u64c7\u6027\u57f7\u884c\u4e0d\u540c\u7684\u7a0b\u5f0f\u78bc\u584a\u3002\u5176\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n
\nCASE\n    WHEN condition1 THEN\n        -- \u57f7\u884c\u7684\u7a0b\u5f0f\u78bc\n    WHEN condition2 THEN\n        -- \u5176\u4ed6\u7a0b\u5f0f\u78bc\n    ELSE\n        -- \u9810\u8a2d\u7a0b\u5f0f\u78bc\nEND CASE;\n<\/code><\/pre>\n
\u4f8b\u5982\uff0c\u6839\u64da\u4e0d\u540c\u7684\u5b78\u751f\u6210\u7e3e\u7d66\u4e88\u4e0d\u540c\u7684\u8a55\u50f9\uff1a<\/p>\n
\nCASE\n    WHEN score >= 90 THEN\n        grade = 'A';\n    WHEN score >= 80 THEN\n        grade = 'B';\n    ELSE\n        grade = 'C';\nEND CASE;\n<\/code><\/pre>\n
3. LOOP\u5b50\u53e5<\/h2>\n
LOOP\u5b50\u53e5\u7528\u65bc\u91cd\u8907\u57f7\u884c\u4e00\u6bb5\u7a0b\u5f0f\u78bc\uff0c\u76f4\u5230\u6eff\u8db3\u7279\u5b9a\u689d\u4ef6\u70ba\u6b62\u3002\u5176\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n
\nLOOP\n    -- \u57f7\u884c\u7684\u7a0b\u5f0f\u78bc\n    IF condition THEN\n        LEAVE;\n    END IF;\nEND LOOP;\n<\/code><\/pre>\n
\u4f8b\u5982\uff0c\u8a08\u7b97\u5f9e1\u523010\u7684\u7e3d\u548c\uff1a<\/p>\n
\nsum = 0;\ncounter = 1;\n\nLOOP\n    sum = sum + counter;\n    counter = counter + 1;\n    IF counter > 10 THEN\n        LEAVE;\n    END IF;\nEND LOOP;\n<\/code><\/pre>\n
4. WHILE\u5b50\u53e5<\/h2>\n
WHILE\u5b50\u53e5\u5141\u8a31\u5728\u689d\u4ef6\u70ba\u771f\u6642\u91cd\u8907\u57f7\u884c\u7a0b\u5f0f\u78bc\u3002\u5176\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n
\nWHILE condition DO\n    -- \u57f7\u884c\u7684\u7a0b\u5f0f\u78bc\nEND WHILE;\n<\/code><\/pre>\n
\u4f8b\u5982\uff0c\u4f7f\u7528WHILE\u8a08\u7b97\u5f9e1\u523010\u7684\u7e3d\u548c\uff1a<\/p>\n
\nsum = 0;\ncounter = 1;\n\nWHILE counter <= 10 DO\n    sum = sum + counter;\n    counter = counter + 1;\nEND WHILE;\n<\/code><\/pre>\n
5. FOR\u5b50\u53e5<\/h2>\n
FOR\u5b50\u53e5\u7528\u65bc\u5728\u6307\u5b9a\u7bc4\u570d\u5167\u91cd\u8907\u57f7\u884c\u7a0b\u5f0f\u78bc\u3002\u5176\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n
\nFOR counter IN start..end DO\n    -- \u57f7\u884c\u7684\u7a0b\u5f0f\u78bc\nEND FOR;\n<\/code><\/pre>\n
\u4f8b\u5982\uff0c\u4f7f\u7528FOR\u8a08\u7b97\u5f9e1\u523010\u7684\u7e3d\u548c\uff1a<\/p>\n
\nsum = 0;\n\nFOR counter IN 1..10 DO\n    sum = sum + counter;\nEND FOR;\n<\/code><\/pre>\n
\u7e3d\u7d50<\/h2>\n
DB2\u7684\u6d41\u7a0b\u63a7\u5236\u5b50\u53e5\u70ba\u958b\u767c\u8005\u63d0\u4f9b\u4e86\u9748\u6d3b\u7684\u5de5\u5177\u4f86\u63a7\u5236\u7a0b\u5f0f\u7684\u57f7\u884c\u6d41\u7a0b\u3002\u900f\u904eIF-THEN-ELSE\u3001CASE\u3001LOOP\u3001WHILE\u548cFOR\u7b49\u5b50\u53e5\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u6839\u64da\u4e0d\u540c\u7684\u9700\u6c42\u8a2d\u8a08\u51fa\u9ad8\u6548\u7684\u8cc7\u6599\u8655\u7406\u908f\u8f2f\u3002\u9019\u4e9b\u6d41\u7a0b\u63a7\u5236\u5b50\u53e5\u4e0d\u50c5\u63d0\u9ad8\u4e86\u7a0b\u5f0f\u7684\u53ef\u8b80\u6027\uff0c\u4e5f\u589e\u5f37\u4e86\u5176\u529f\u80fd\u6027\u3002<\/p>\n
\u5982\u679c\u60a8\u5c0d\u65bc\u8cc7\u6599\u5eab\u7ba1\u7406\u6216\u5176\u4ed6\u76f8\u95dc\u6280\u8853\u6709\u8208\u8da3\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4e86\u89e3\u66f4\u591a\u8cc7\u8a0a\uff0c\u7279\u5225\u662f\u6211\u5011\u7684\u9999\u6e2fVPS<\/a>\u89e3\u6c7a\u65b9\u6848\uff0c\u70ba\u60a8\u7684\u696d\u52d9\u63d0\u4f9b\u7a69\u5b9a\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u63a2\u7d22DB2\u6d41\u7a0b\u63a7\u5236\u5b50\u53e5\u7684\u5168\u9762\u6307\u5357\uff0c\u4e86\u89e3\u5404\u7c7b\u5b50\u53e5\u7684\u529f\u80fd\u4e0e\u5e94\u7528\uff0c\u63d0\u5347\u6570\u636e\u5e93\u7ba1\u7406\u6548\u7387\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-60575","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60575","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=60575"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60575\/revisions"}],"predecessor-version":[{"id":60576,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60575\/revisions\/60576"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=60575"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=60575"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=60575"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}