我正在用 JAVA 編輯 SQL，但不斷收到 ERROR
如果我理解正確，如果狀態正常，我應該得到
SELECT name FROM inventura_table where state='O'
當我通過腳本執行相同的選擇時，它作業得很好
Connection conn = DriverManager.getConnection(url, user, password);
String SQL = "SELECT name FROM inventura_table where ?";
PreparedStatement pstmt = conn.prepareStatement(SQL);
ResultSet rs;
switch (state) {
case "OK":
pstmt.setString(1, "state='O' ");
break;
case "M":
pstmt.setString(1, "state='M' ");
break;
case "V":
pstmt.setString(1, "state='V' ");
break;
case "removed":
pstmt.setString(1, "out_date IS NOT NULL");
break;
}
錯誤
錯誤：WHERE 的引數必須是布爾型別，而不是字符變化型別
uj5u.com熱心網友回復：
你正在嘗試的是不可能的。您只能為條件設定值，而不能創建新條件。
你可以這樣做：
Connection conn = DriverManager.getConnection(url, user, password);
String SQL = "SELECT name FROM inventura_table";
if (state.equals("removed")) {
SQL = " where out_date IS NOT NULL";
}
else {
SQL = " where state = ?";
}
PreparedStatement pstmt = conn.prepareStatement(SQL);
ResultSet rs;
switch (state) {
case "OK":
pstmt.setString(1, "O");
break;
case "M":
pstmt.setString(1, "M");
break;
case "V":
pstmt.setString(1, "V");
break;
}
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標籤：爪哇sql
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