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异常:Driver class 'org.gjt.mm.mysql.Driver' could not be found, make sure the 'MySQL' driver (jar file) is installed.org.gjt.mm.mysql.Driver Link1:https 阅读全文
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Sql SELECT ITEM_DATE, TO_CHAR(ITEM_DATE, 'YYYY-MM-DD') CURRENT_DATE_STR, CURRENT_YEAR, CASE TO_CHAR(ITEM_DATE, 'MM') WHEN '01' THEN 'JAN' WHEN '02' TH 阅读全文
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简单删除 DELETE TABLE_NAME WHERE KEY = 1; DELETE TABLE_NAME WHERE KEY IN (1, 2, 3); DELETE TABLE_NAME WHERE KEY IN (SELECT 1 FROM DUAL); 多条件删除 1.EXISTS DE 阅读全文
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查询所有表对应的数据量 1.GROUP SELECT A.NAME AS 表名, MAX(B.ROWS) AS 记录条数 FROM SYS.SYSOBJECTS AS A INNER JOIN SYS.SYSINDEXES AS B ON A.ID = B.ID AND (A.XTYPE = 'U' 阅读全文
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导入命名空间 using System.Data.SqlClient; 代码 var sqlBuilder = new StringBuilder("SELECT SUM(TOTAL) AS TOTAL FROM ("); sqlBuilder.Append(" SELECT COUNT(1) AS 阅读全文