Through this article, you learned how to use the SQL LIKE operator to match the records match a condition. You also learned how to specify multiple conditions in the LIKE operator. Thanks for reading!! About the author John Otieno My name is John and am a fellow geek like you. I am pa...
SQL requires single quotes around text values (most database systems will also allow double quotes).However, numeric fields should not be enclosed in quotes:Example SELECT * FROM Customers WHERE CustomerID=1; Try it Yourself » Note: The WHERE clause is not only used in SELECT statement, ...
向hive表中加载数据 直接向分区表中插入数据:insert into table score partition(month ='202107') values ('001','002','100'); 通过load方式加载数据:load data local inpath '/export/servers/hivedatas/score.csv' overwrite into table score partition(month='201806'); 通过查询方式加载数据:insert overwr...
explain select * from t1 where exists (select * from t2 where t1.c1 <> t2.c1); #NSET2: [19, 1, 0] #PRJT2: [19, 1, 0]; exp_num(3), is_atom(FALSE) #NEST LOOP SEMI JOIN2: [19, 1, 0]; join condition(T1.C1 <> T2.C1) #CSCN2: [6, 1, 0]; INDEX33555480(T1) ...
SELECT * FROM test WHERE test_value LIKE '%!%%' escape '!'; These are the results that you should see: test_idtest_value 110% 225% This example identifies the!character as an escape character. The first and last%values in the LIKE condition are treated as regular wildcards. The!%is...
insert into user(email,name) values('aaa@','aaa'); 1062 - Duplicate entry 'aaa@' for key 'uk-email', Time: 0.005000s 1. 2. 3. 4. 5. 6. 此时对于唯一性来说是没问题的,可以保证业务的email的唯一性。假设随着业务的发展,此时需要增加手机号注册功能,那么表中就需要增加手机号字段,且需要保...
1.where子句优化 官方文档:WHERE Clause Optimization 这里总结where语句的优化,以select为例,但同样适用于update和delete语句。 2.Range Optimization(范围优化) 官方文档:Range Optimization 3.Index Merge Optimization(索引合并优化) 官方文档:Index Merge Optimization ...
WHERE condition1 OR condition2 ... OR condition_n; Parameters or Arguments condition1, condition2, ... condition_n Multiple conditions that will be tested for each record. Any condition can be met to be included in the result set.
explain select * from t1 where (c1, c2) not in (select c1, c2 from tx); #NSET2: [35, 1, 0] #PRJT2: [35, 1, 0]; exp_num(3), is_atom(FALSE) #HASH LEFT SEMI MULTIPLE JOIN: [35, 1, 0]; (ANTI), join condition((exp11 AND exp11)) #CSCN2: [6, 1, 0]; INDEX...
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