3.1. UsingIS NULLOperator Let’s write the SQL query to filter the rows with empty strings or null values in thecodecolumn: SELECT id, name FROM Department WHERE code IS NULL OR code = ''; Here, we used theORcondition within theWHEREclause to combine two conditions. TheIS NULLoperator ...
0 rows affected, 1 warning (0.00 sec) mysql> flush privileges; Query OK, 0 rows affected (0.01 sec) PS:必须执行flush privileges; 否则登录时提示:ERROR 1045 (28000): Access denied for user 'user'@'localhost' (using password: YES
if (mtxtCounty==null) mtxtCountry=""; before the Linq query. Tuesday, April 12, 2016 4:40 PM Hello! Stewa before executing the linq query first check that mtxtCounty(text field) is empty or not then use if else case like below ...
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:870) at com.mysql.jdbc.StatementImpl.checkNullOrEmptyQuery(StatementImpl.java:492) at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1367) at com.you.sql.Student.queryStudent(Student.java:51) at com.you.sql.Student.main(S...
at com.mysql.jdbc.StatementImpl.checkNullOrEmptyQuery(StatementImpl.java:492) at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1367) at com.you.sql.Student.queryStudent(Student.java:51) at com.you.sql.Student.main(Student.java:79) ...
public List<Category> getCategory(List<Long> ids) { if(CollectionUtils.isEmpty(ids)) { return null; } if(ids.size() > 500) { throw new BusinessException("一次最多允许查询500条记录") } return mapper.getCategoryList(ids); } 还有一个方案就是:如果ids超过500条记录,可以分批用多线程去查询...
public static void queryStudent() { StringBuffer sql = new StringBuffer(); String url = "jdbc:mysql://localhost:3333/student"; String user = "root"; String password = "root"; Connection conn = null; Statement stat = null; ResultSet rs = null; ...
|4|小蓝|13|北京|NULL| |5|小黑|14|北京|NULL| +---+---+---+---+---+ 5rowsinset(0.00sec) 2.8 从库建立复制 greatsql>reset master; Query OK,0rowsaffected (0.04sec) greatsql>setglobalgtid_purged='b94e6517-68dd-11ee-b43b-00163ecb92e3:1-5755'; Query OK,0rowsaffected (0.00...
It returns NULL. The solution to getting all entries was to wrap string_field in COALESCE, which converts NULL to an empty string. 代码语言:javascript 代码运行次数:0 运行 AI代码解释 SELECTCOUNT(*)AScFROMtable1ASt1JOINtable2ASt2ONCOALESCE(t1.string_field,'')=COALESCE(t2.string_field,'')...
ODPS-0121055:Empty argument value 模块:PROCESSOR。 严重等级:5。 触发条件:参数为空或NULL。 处理方法:修改入参。 ODPS-0121065:Argument value out of range 模块:PROCESSOR。 严重等级:5。 触发条件:参数值错误,超出允许范围。 处理方法:修改参数值。