Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1p3cua-00028Y-7B for pgsql-sql@arkaria.postgresql.org; Fri, 09 Dec 2022 12:55:32 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1p3cuZ-0006aB-3f for pgsql-sql@arkaria.postgresql.org; Fri, 09 Dec 2022 12:55:31 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1p3cuY-0006Zt-Pg for pgsql-sql@lists.postgresql.org; Fri, 09 Dec 2022 12:55:30 +0000 Received: from mail-ed1-x52b.google.com ([2a00:1450:4864:20::52b]) by magus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1p3cuX-00033T-Ge for pgsql-sql@lists.postgresql.org; Fri, 09 Dec 2022 12:55:30 +0000 Received: by mail-ed1-x52b.google.com with SMTP id l11so2972046edb.4 for ; Fri, 09 Dec 2022 04:55:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=to:subject:message-id:date:from:mime-version:from:to:cc:subject :date:message-id:reply-to; bh=s7lv1P4nzGde5KyvC2nevn9OxkWqrylg/Kf/robXA6M=; b=L66srmlwvGv1zOsE9q4sM4CKpYVUtdeZ2YmkR0hXEjGwWOiOAMf3EwT+J31OXQQlse oY7Z+7SmDiPlFFxnFbW1mhLYXtpOrQdw1ZClzbrVHrT28Kbv3t9vx2dQGTnWJbywWcO7 T3HZ0sn2bSm5HkyUFCv8QtPjwB4qq1tceflwkfFXJPQcpBGYs2ChBbjzu92pEOZcbYku c7aFfCEdt89sTf0fWsFyDdwsBU3qgUr5fv05SQ9j9YpZPkaTjmRuDHot1J03tPcZtH0H T1Af50zjN1IBeShVjTVZaucX9Ag8TDyKKgyWxgP0P93P+xxvvss5uZuplOisUrHGSah7 Wt7g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:subject:message-id:date:from:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=s7lv1P4nzGde5KyvC2nevn9OxkWqrylg/Kf/robXA6M=; b=6QE98hty8q7KviIxMA/0CdSFxPPE4FtR//Vo8wtZT7C99/pMVEGbLrHNVElx2utnH+ 80jcpiMD+ygxSpIOmaSwpYQurjKMGYGjvDlbmZ0YzEsx6ORCNJLKdOUhgfr2tAmN8Oas aImQDfAkSW9sRGFoUaUhGSjws1VtdZUQhTGvu1dQc0KzyaMlJFnmUF5ohCQYFak0qXiG LJh2oMgotX8sJY1CChHIDfICtmZUGgc+QDrQK7pwDG8fBWJW4ajEs3gAiQO+w/R40yND lVF5blp+oY+IGqqYRqqjeJK7C3bjT2Uyf0fvs0aTjQLoTg6SgmmJ9YjJn7e911WgdvR4 vxDg== X-Gm-Message-State: ANoB5pnoE+wyUWnmr/q86nkcfKB46HHxMWikkEJujTQPuLhFAcaxP5Yv t8n1dJTwJzG7wQh8O5gMsDZOuVZbe6eHOoeV4nUjqni1iDw= X-Google-Smtp-Source: AA0mqf79I4DikzFaPe0htWw13KQAcFDLxXOfmtsow+1pqSkGRyS0hkYxHAb6lrZNE4AVvGcvpw16Npu5ywT1VthwNgo= X-Received: by 2002:aa7:c90a:0:b0:46c:a9ce:9800 with SMTP id b10-20020aa7c90a000000b0046ca9ce9800mr16271192edt.218.1670590527662; Fri, 09 Dec 2022 04:55:27 -0800 (PST) MIME-Version: 1.0 From: Shaozhong SHI Date: Fri, 9 Dec 2022 12:55:16 +0000 Message-ID: Subject: Change detection To: pgsql-sql Content-Type: multipart/alternative; boundary="000000000000f76f5505ef64aac9" List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk --000000000000f76f5505ef64aac9 Content-Type: text/plain; charset="UTF-8" A record shows all staff member worked in different departments. For instance, Tom was in sales for several years and got promoted to management. How to detect the time of this change? Data Staff_ID Name Department Year 1 Tom Sales 1990 2 Tom Sales 1991 3 Tom Sales 1991 4 Tom Management 1992 4 Tom Management 1992 Regards, David --000000000000f76f5505ef64aac9 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: base64 PGRpdiBkaXI9Imx0ciI+PGRpdiBkaXI9Imx0ciI+PGRpdiBkaXI9Imx0ciI+PGRpdiBkaXI9Imx0 ciI+PGRpdiBkaXI9Imx0ciI+QSByZWNvcmQgc2hvd3MgYWxsIHN0YWZmIG1lbWJlciB3b3JrZWQg aW4gZGlmZmVyZW50IGRlcGFydG1lbnRzLjxkaXY+PGJyPjwvZGl2PjxkaXY+Rm9yIGluc3RhbmNl LCBUb20gd2FzIGluIHNhbGVzIGZvciBzZXZlcmFsIHllYXJzIGFuZCBnb3QgcHJvbW90ZWQgdG8g bWFuYWdlbWVudC7CoCDCoEhvdyB0byBkZXRlY3QgdGhlIHRpbWUgb2YgdGhpcyBjaGFuZ2U/PC9k aXY+PGRpdj48YnI+PC9kaXY+PGRpdj5EYXRhPC9kaXY+PGRpdj48YnI+PC9kaXY+PGRpdj5TdGFm Zl9JRMKgIMKgIE5hbWXCoCDCoERlcGFydG1lbnTCoCDCoCDCoCDCoCDCoCDCoCBZZWFyPC9kaXY+ PGRpdj4xwqAgwqAgwqAgwqAgwqAgwqAgwqAgwqAgVG9twqAgwqAgU2FsZXPCoCDCoCDCoCDCoCDC oCDCoCDCoCDCoCDCoCDCoCDCoDE5OTA8L2Rpdj48ZGl2PjLCoCDCoCDCoCDCoCDCoCDCoCDCoCDC oCDCoFRvbcKgIMKgIMKgIFNhbGVzwqAgwqAgwqAgwqAgwqAgwqAgwqAgwqAgwqAgwqAxOTkxPC9k aXY+PGRpdj4zwqAgwqAgwqAgwqAgwqAgwqAgwqAgwqAgwqBUb23CoCDCoCDCoCBTYWxlc8KgIMKg IMKgIMKgIMKgIMKgIMKgIMKgIMKgIMKgMTk5MTxicj48L2Rpdj48ZGl2PjTCoCDCoCDCoCDCoCDC oCDCoCDCoCDCoCDCoFRvbcKgIMKgIMKgIE1hbmFnZW1lbnTCoCDCoCDCoCDCoCDCoDE5OTI8YnI+ PC9kaXY+PGRpdj40wqAgwqAgwqAgwqAgwqAgwqAgwqAgwqAgwqBUb23CoCDCoCDCoE1hbmFnZW1l bnTCoMKgIMKgIMKgIMKgIMKgIDE5OTI8YnI+PC9kaXY+PGRpdj48YnI+PC9kaXY+PGRpdj48YnI+ PC9kaXY+PGRpdj5SZWdhcmRzLDwvZGl2PjxkaXY+PGJyPjwvZGl2PjxkaXY+RGF2aWQ8L2Rpdj48 L2Rpdj48L2Rpdj48L2Rpdj48L2Rpdj48L2Rpdj4NCg== --000000000000f76f5505ef64aac9--