我有一个带有case语句的SQL查询。 case语句具有一个子查询。我想用联接替换（删除）子选择。有可能的？我该怎么办？
查询：
SELECT tablex.Abnumber, CASE WHEN Abdate is not null AND isnull(Abnumber,0) > 1 AND Abdate < (SELECT Abdate FROM t_tablex WHERE Annumber = @Annumber AND Abnumber= @Abnumber-1) THEN 'bla bla' ELSE '' END
FROM t_tablex AS tablex
WHERE (@Annumber IS NULL OR tablex.Annumber= @Annumber)
AND (@AbnumberIS NULL OR tablex.Abnumber= @Abnumber)
答案 0 :(得分：0)
SELECT tablex.Abnumber,
CASE WHEN isnull(Abnumber,0) > 1 AND Abdate < a.Abdate THEN 'bla bla' ELSE '' END
FROM t_tablex AS tablex
LEFT JOIN (SELECT Abdate
FROM t_tablex
WHERE Annumber = @Annumber AND Abnumber= @Abnumber-1
) A ON A.Annumber = tablex.Annumber AND a.Abnumber = tablex.Abnumber
WHERE tablex.Annumber= @Annumber
AND tablex.Abnumber= @Abnumber
答案 1 :(得分：0)
我怀疑function dumpSMSintoSender() {
var MOVED_TO_SENDER = "Yes";
var userSheet = SpreadsheetApp.getActiveSpreadsheet();
var userTab = userSheet.getSheetByName('SmartCare');
var SenderTab = userSheet.getSheetByName('Sheet1');
var numRows = 200
var firstRow = 2;
var range = userTab.getRange(firstRow, 3, userTab.getLastRow() - firstRow +1, 3);
var data = range.getValues();
var dataRange = userTab.getRange(firstRow, 3, numRows, 10)
// Fetch values for each row in the Range.
var Movedata = dataRange.getValues();
for (var i = 0; i < Movedata.length; ++i) {
var row = Movedata[i];
var MovedtoSender = row[5];
var sender = row[0];
var mobile = row[1];
var message = row[2];
if (mobile != "") {
if (MovedtoSender != MOVED_TO_SENDER) { // Prevents sending duplicates
SenderTab.getRange(SenderTab.getLastRow() + 1, 1, data.length,3).setValues(data);
userTab.getRange(firstRow + i, 8).setValue("Yes");
// Make sure the cell is updated right away in case the script is interrupted
SpreadsheetApp.flush();
}
}
}
}
是您想要的：
LAG()这与您的查询完全不同，除非对数据做出一些假设。但是，我怀疑这实际上是您想要的。
答案 2 :(得分：0)
感谢您的回答。我做了一些尝试，发现了以下解决方案：
解决方案1（用内部联接替换子选择）：
SELECT tablex.Abnumber,
CASE WHEN tablex.Abdate is not null
AND isnull(tablex.Abnumber,0) > 1
AND tablex.Abdate < tablex2.Abdate
THEN 'bla bla'
ELSE '' END
FROM t_tablex AS tablex
INNER JOIN t_tablex as tablex2
ON tablex.Annumber = tablex2.Annumber
AND tablex.Abnumber = tablex2.Abnumber + 1
WHERE tablex.Annumber = ISNULL( @Annumber, tablex.Annumber)
AND tablex.Abnumber = ISNULL( @Abnumber, tablex.Abnumber)
解决方案2（使用LAG（））：
SELECT base.*
FROM (
SELECT tablex.Abnumber,
CASE WHEN tablex.Abdate is not null
AND tablex.Abnumber > 1
AND tablex.Abdate < LAG( tablex.Abdate, 1 ) OVER ( PARTITION BY tablex.Annumber ORDER BY tablex.Abnumber)
THEN 'bla bla'
ELSE '' END AS ERG
FROM t_tablex AS tablex
WHERE tablex.Annumber = ISNULL( @Annumber, tablex.Annumber )
AND tablex.Abnumber BETWEEN ISNULL( @Abnumber , tablex.Abnumber) - 1
AND ISNULL( @Abnumber, tablex.Abnumber )
) base
WHERE
base.Abnumber = ISNULL( @Abnumber, base.Abnumber )