sendStringParametersAsUnicode

JDBC預設是true，會自動把字元資料轉成Unicode格式送到伺服器

但是資料庫column不是開nchar之類的Unicode UCS-2欄位

因為SQL Server需要做型別轉換，會需要用到平行處理，會很耗cpu

從執行計畫可以看到"type conversion in expression"的警告訊息

解法一:column改成nvarvhar nchar這類的欄位

解法二:sendStringParametersAsUnicode設定成false，使用非Unicode格式送到伺服器(比如ASCII/MBCS)

今天上許致學老師的課才知道有這參數

https://sqlwizard.blog/2018/07/29/performance-impact-of-jdbc-connectionstring-property-sendstringparametersasunicode/

https://community.jaspersoft.com/wiki/microsoft-sqlserver-jdbc-connection-sending-string-values-unicode-even-if-they-are-just-simple

https://docs.microsoft.com/zh-tw/sql/connect/jdbc/reference/setsendstringparametersasunicode-method-sqlserverdatasource?view=sql-server-ver15

"type conversion in expression" sql server

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