mongodb inner join

When querying for data. It's strange to write a piece of SQL. No duplicate data occurs when you query data from the first 5 tables There is a lot of duplicate data until the sixth table is associated (t_im_inventorybalance ). For a time it was depressing. Then consult the implementation personnel to know. The original t_im_inventorybalance itself has multiple duplicate data, which means that when Material.fid = Ib.fmaterialid Association It's a one-to-many relationship. Multiple conditions need

Below ABAP Syntax is ABAP Inner Join example. Start-of-selection. * Assumption:all quantities is in sales units. Since quantities * be summed to the material group level, it's assumed that all * Materials within a material group has the same sales unit of * measure. Select A~kunag A~vbeln a~fkdat a~bukrs A~vbtyp B~MATKL b~matnr b~arktx b~fkimg b~kzwi2 B~WAVWR C~name1 D~kunn2 into corresponding fields of ta

Prerequisites: Assume there are two tables Table1: ID data 1 2 B 3 C Table2: ID data 1 2 B 4 d Question: 1. If you want to find the same data in Table1 and Table2, The SQL statement is: Select table1.id, table1.data, table2.id, table2.dataFrom Table1 inner join Table2 on (table1.data = table2.data) and (table1.id = table2.id ); The query result is: Table1_id Tabledomaindata T

Copy codeThe Code is as follows:-- QuerySELECT tp. tp_id, tp. tpmc, tp. leveid, tp. tpdz, tp. jgm, tp. scsj, tp. pbzyid, tp. ksbfsj, tp. jsbfsj, tp. status, tp. tpbz FROM qdgl_tupian tp inner join qdgl_pqb pqON tp. tp_id = pq. tpid WHERE pq. bfjgm = '000000' AND ps_bfsj> = '2017-01 'AND ps_bfsj Copy codeThe Code is as follows:-- ModifyUPDATE jx_lsjl jx inner

[Mysql] basic concepts of primary keys and Foreign keys for multi-table queries using inner join and nested queries Although multi-table queries are required in computer science and databases, many teachers have not thoroughly explained this difficulty. It's confusing to have a bunch of things that are connected to the left and the right. The instructor will tell you all the multi-Table query methods, but o

Copy Code code as follows: --Query SELECT tp.tp_id, TP.TPMC, Tp.leveid, Tp.tpdz, TP.JGM, TP.SCSJ, Tp.pbzyid, TP.KSBFSJ, TP.JSBFSJ, Tp.status, TP.TPBZ from QD Gl_tupian TP INNER JOIN QDGL_PQB PQ On Tp.tp_id=pq.tpid WHERE pq.bfjgm= ' 27010825 ' and PS_BFSJ >= ' 2013-01 ' and ps_bfsj Copy Code code as follows: --Modify UPDATE jx_lsjl jx INNER

SQL INNER JOIN keywordThe INNER JOIN keyword returns a row when there is at least one match in the table.INNER JOIN keyword SyntaxSELECT column_name (s) from Table_name1inner JOIN table_name2 on Table_name1.column_name=table_name2

SQL INNER JOIN keywordThe INNER JOIN keyword returns a row when there is at least one match in the table.INNER JOIN keyword SyntaxSELECT column_name (s) from Table_name1inner JOIN table_name2 on Table_name1.column_name=table_name2

In the following example, 3 Join methods are implemented to connect two DataTable, equivalent to the SQL inner join method, and return all columns of the DataTable.If the DataColumn in the two DataTable is duplicated, the second is set to Columnname+ "_second", and the following code is in the hope of helping.Using System;Using System.Data; Namespace WindowsAppli

Today, I helped developers optimize SQL and found a problem that I didn't care much about before. SELECTbond.store_noFROMbill_order_num_dtlbondWHEREEXISTS(select1frommeetorder_staff_dtlb,meetorder_staffawhereb.operate_area=bond.store_noanda.seq_no=b.seq_noanda.user_code=‘lym‘); The query requires 2 s, bill_order_num_dtl has more than 2 W data records, and meetorder_staff_dtl has about 50 records. After replacing exists with inner

The Inner join is where the two tables do the same part of the record to produce a recordset, Union is the resulting two recordset (field to be the same) and together to become a new recordset Select a.field1,b.field2 from Table1 A inner join Table2 B on A.field2=b.field2 where .... Select Field1 from Table1 Union se

In MySQL paging optimization, when does the "inner join mode optimization paging algorithm" take effect ?, Innerjoin Source: http://www.cnblogs.com/wy123/p/7003157.html I recently accidentally saw a MySQL paging optimization test case. I did not explain the test scenario very specifically. I gave a classic solution,In reality, many situations are not fixed, so we need to consider a lot of scenarios when w

Label:Background: You want to improve the efficiency of queries, starting with the frequently occurring subqueries in SQL statements. The data table is as follows: The Citycode in the student table corresponds to code in the city table. Student table: City table: Sub-query mode: The SQL statements are as follows: 1 Select from Student 2 where Citycode 3 inch 4 (select from city) Inner Connection mode:The SQL statements are as follows: 1 Select

do the filter, you can quickly drop to find the current page of data, so of course, there is no problem, but this is another approach, is not discussed in this article.SummarizePaging query, the more slow the situation, but in fact, for the B-tree index, front and back is a logical relative concept, performance differences, based on the B-tree index structure and scanning methods.If you add a filter, the situation becomes more complex, and the same is true in SQL Server, which is also tested in

Using the SQL INNER JOIN keyword Tutorial INNER JOIN keyword When returning rows at least one race in the table.SQL syntax for INNER JOIN SELECT column_name (s) from table_name1 INNER