{"id":5976,"date":"2024-11-14T10:42:53","date_gmt":"2024-11-14T02:42:53","guid":{"rendered":"https:\/\/fwq.ai\/blog\/5976\/"},"modified":"2024-11-14T10:42:53","modified_gmt":"2024-11-14T02:42:53","slug":"sql-declare%e6%98%af%e5%95%a5%e6%84%8f%e6%80%9d","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/5976\/","title":{"rendered":"sql declare\u662f\u5565\u610f\u601d"},"content":{"rendered":"

\n \u5728 sql \u4e2d\uff0cdeclare \u8bed\u53e5\u7528\u4e8e\u58f0\u660e\u53d8\u91cf\u6216\u6e38\u6807\uff0c\u5141\u8bb8\u5728\u7a0b\u5e8f\u6267\u884c\u671f\u95f4\u5b58\u50a8\u548c\u4f7f\u7528\u6570\u636e\u3002\u53d8\u91cf\u7528\u4e8e\u5b58\u50a8\u5355\u4e2a\u503c\uff0c\u800c\u6e38\u6807\u7528\u4e8e\u904d\u5386\u7ed3\u679c\u96c6\u3002declare \u8bed\u53e5\u8fd8\u53ef\u7528\u4e8e\u5b58\u50a8\u4e2d\u95f4\u7ed3\u679c\u3001\u904d\u5386\u7ed3\u679c\u96c6\u548c\u5c06\u503c\u4f20\u9012\u7ed9\u5b58\u50a8\u8fc7\u7a0b\u6216\u51fd\u6570\u3002\n<\/p><\/blockquote>\n

\"sql<\/p>\n

SQL \u4e2d DECLARE \u7684\u542b\u4e49<\/strong><\/p>\n

\u5728 SQL \u4e2d\uff0cDECLARE \u8bed\u53e5\u7528\u4e8e\u58f0\u660e\u53d8\u91cf\u6216\u6e38\u6807\u3002\u5b83\u5141\u8bb8\u5f00\u53d1\u8005\u5728\u7a0b\u5e8f\u6267\u884c\u8fc7\u7a0b\u4e2d\u5b58\u50a8\u548c\u4f7f\u7528\u6570\u636e\u3002<\/p>\n

\u8bed\u6cd5<\/strong><\/p>\n

DECLARE [variable_name] [data_type] [DEFAULT default_value];<\/pre>\n
  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n
\u53d8\u91cf<\/strong><\/p>\n
\u53d8\u91cf\u7528\u4e8e\u5b58\u50a8\u5355\u4e2a\u503c\uff0c\u5b83\u53ef\u4ee5\u662f\u4efb\u4f55\u6709\u6548\u7684\u6570\u636e\u7c7b\u578b\uff0c\u5982\u6574\u6570\u3001\u5b57\u7b26\u4e32\u6216\u65e5\u671f\u3002\u4f7f\u7528DECLARE\u8bed\u53e5\u58f0\u660e\u53d8\u91cf\u540e\uff0c\u53ef\u4ee5\u901a\u8fc7\u53d8\u91cf\u540d\u6765\u8bbf\u95ee\u5b83\u7684\u503c\u3002<\/p>\n
\u6e38\u6807<\/strong><\/p>\n
\u6e38\u6807\u7528\u4e8e\u904d\u5386\u7ed3\u679c\u96c6\u4e2d\u7684\u884c\u3002\u58f0\u660e\u6e38\u6807\u65f6\uff0c\u9700\u8981\u6307\u5b9a\u4e00\u4e2a\u6e38\u6807\u540d\u548c\u5b83\u6240\u6307\u5411\u7684 SQL \u8bed\u53e5\u3002\u6e38\u6807\u53ef\u4ee5\u7528\u6765\u9010\u884c\u8bfb\u53d6\u7ed3\u679c\u96c6\uff0c\u5e76\u4f7f\u7528 FETCH \u8bed\u53e5\u6765\u83b7\u53d6\u5f53\u524d\u884c\u7684\u6570\u636e\u3002<\/p>\n
\u793a\u4f8b<\/strong><\/p>\n
-- \u58f0\u660e\u4e00\u4e2a\u540d\u4e3a @total \u7684\u6574\u6570\u53d8\u91cf\uff0c\u5e76\u5c06\u5176\u9ed8\u8ba4\u503c\u8bbe\u7f6e\u4e3a 0\nDECLARE @total INT DEFAULT 0;\n\n-- \u58f0\u660e\u4e00\u4e2a\u540d\u4e3a @result \u7684\u6e38\u6807\uff0c\u5b83\u6307\u5411\u8fd4\u56de\u6240\u6709\u5ba2\u6237\u7684 SQL \u8bed\u53e5\nDECLARE @result CURSOR FOR\nSELECT * FROM Customers;<\/pre>\n
  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n
\u7528\u9014<\/strong><\/p>\n
DECLARE \u8bed\u53e5\u5728\u4ee5\u4e0b\u60c5\u51b5\u4e0b\u5f88\u6709\u7528\uff1a<\/p>\n
    \n
  • \u5b58\u50a8\u4e2d\u95f4\u7ed3\u679c\uff0c\u4ee5\u4fbf\u5728\u7a0b\u5e8f\u4e2d\u591a\u6b21\u4f7f\u7528<\/li>\n
  • \u904d\u5386\u7ed3\u679c\u96c6\u5e76\u5bf9\u5176\u4e2d\u7684\u884c\u8fdb\u884c\u64cd\u4f5c<\/li>\n
  • \u5c06\u503c\u4f20\u9012\u7ed9\u5b58\u50a8\u8fc7\u7a0b\u6216\u51fd\u6570<\/li>\n<\/ul>\n
    \u4ee5\u4e0a\u5c31\u662fsql declare\u662f\u5565\u610f\u601d\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u7f51\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
    \u5728 sql \u4e2d\uff0cdeclare \u8bed\u53e5\u7528\u4e8e\u58f0\u660e\u53d8\u91cf\u6216\u6e38\u6807\uff0c\u5141\u8bb8\u5728\u7a0b\u5e8f\u6267\u884c\u671f\u95f4\u5b58\u50a8\u548c\u4f7f\u7528\u6570\u636e\u3002\u53d8\u91cf\u7528\u4e8e\u5b58\u50a8\u5355\u4e2a\u503c\uff0c\u800c\u6e38\u6807\u7528\u4e8e\u904d\u5386\u7ed3\u679c\u96c6\u3002declare \u8bed\u53e5\u8fd8\u53ef\u7528\u4e8e\u5b58\u50a8\u4e2d\u95f4\u7ed3\u679c\u3001\u904d\u5386\u7ed3\u679c\u96c6\u548c\u5c06\u503c\u4f20\u9012\u7ed9\u5b58\u50a8\u8fc7\u7a0b\u6216\u51fd\u6570\u3002 SQL \u4e2d DECLARE \u7684\u542b\u4e49 \u5728 SQL \u4e2d\uff0cDECLARE \u8bed\u53e5\u7528\u4e8e\u58f0\u660e\u53d8\u91cf\u6216\u6e38\u6807\u3002\u5b83\u5141\u8bb8\u5f00\u53d1\u8005\u5728\u7a0b\u5e8f\u6267\u884c\u8fc7\u7a0b\u4e2d\u5b58\u50a8\u548c\u4f7f\u7528\u6570\u636e\u3002 \u8bed\u6cd5 DECLARE [variable_name] [data_type] [DEFAULT default_value]; \u767b\u5f55\u540e\u590d\u5236 \u53d8\u91cf \u53d8\u91cf\u7528\u4e8e\u5b58\u50a8\u5355\u4e2a\u503c\uff0c\u5b83\u53ef\u4ee5\u662f\u4efb\u4f55\u6709\u6548\u7684\u6570\u636e\u7c7b\u578b\uff0c\u5982\u6574\u6570\u3001\u5b57\u7b26\u4e32\u6216\u65e5\u671f\u3002\u4f7f\u7528DECLARE\u8bed\u53e5\u58f0\u660e\u53d8\u91cf\u540e\uff0c\u53ef\u4ee5\u901a\u8fc7\u53d8\u91cf\u540d\u6765\u8bbf\u95ee\u5b83\u7684\u503c\u3002 \u6e38\u6807 \u6e38\u6807\u7528\u4e8e\u904d\u5386\u7ed3\u679c\u96c6\u4e2d\u7684\u884c\u3002\u58f0\u660e\u6e38\u6807\u65f6\uff0c\u9700\u8981\u6307\u5b9a\u4e00\u4e2a\u6e38\u6807\u540d\u548c\u5b83\u6240\u6307\u5411\u7684 SQL \u8bed\u53e5\u3002\u6e38\u6807\u53ef\u4ee5\u7528\u6765\u9010\u884c\u8bfb\u53d6\u7ed3\u679c\u96c6\uff0c\u5e76\u4f7f\u7528 FETCH \u8bed\u53e5\u6765\u83b7\u53d6\u5f53\u524d\u884c\u7684\u6570\u636e\u3002 \u793a\u4f8b — \u58f0\u660e\u4e00\u4e2a\u540d\u4e3a @total \u7684\u6574\u6570\u53d8\u91cf\uff0c\u5e76\u5c06\u5176\u9ed8\u8ba4\u503c\u8bbe\u7f6e\u4e3a 0 DECLARE @total INT DEFAULT 0; — \u58f0\u660e\u4e00\u4e2a\u540d\u4e3a @result \u7684\u6e38\u6807\uff0c\u5b83\u6307\u5411\u8fd4\u56de\u6240\u6709\u5ba2\u6237\u7684 SQL \u8bed\u53e5 DECLARE @result CURSOR FOR SELECT * FROM Customers; \u767b\u5f55\u540e\u590d\u5236 \u7528\u9014 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-5976","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5976","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=5976"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5976\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=5976"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=5976"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=5976"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}