Adding the LATERAL  keyword makes the query legal: 

SELECT salesperson.name, max_sale.amount, max_sale.customer_name FROM salesperson, -- find maximum size and customer at same time LATERAL (SELECT amount, customer_name FROM all_sales WHERE all_sales.salesperson_id = salesperson.id ORDER BY amount DESC LIMIT 1) AS max_sale; 

In short, LATERAL  is the efficient solution to all drawbacks in the two approaches just discussed. 

## 13.2.11.10 Subquery Errors 

There are some errors that apply only to subqueries. This section describes them. 

•Unsupported subquery syntax: 

ERROR 1235 (ER_NOT_SUPPORTED_YET) SQLSTATE = 42000 Message = "This version of MySQL doesn’t yet support ’LIMIT & IN/ALL/ANY/SOME subquery’" 

This means that MySQL does not support statements like the following: 

SELECT * FROM t1 WHERE s1 IN (SELECT s2 FROM t2 ORDER BY s1 LIMIT 1) 

•Incorrect number of columns from subquery: 

ERROR 1241 (ER_OPERAND_COL) SQLSTATE = 21000 Message = "Operand should contain 1 column(s)" 

This error occurs in cases like this: 

SELECT (SELECT column1, column2 FROM t2) FROM t1; 

You may use a subquery that returns multiple columns, if the purpose is row comparison. In other contexts, the subquery must be a scalar operand. See Section 13.2.11.5, “Row Subqueries” . 

•Incorrect number of rows from subquery: 

ERROR 1242 (ER_SUBSELECT_NO_1_ROW) SQLSTATE = 21000 Message = "Subquery returns more than 1 row" 

This error occurs for statements where the subquery must return at most one row but returns multiple rows. Consider the following example: 

SELECT * FROM t1 WHERE column1 = (SELECT column1 FROM t2); 

If SELECT column1 FROM t2  returns just one row, the previous query works. If the subquery returns more than one row, error 1242 occurs. In that case, the query should be rewritten as: 

SELECT * FROM t1 WHERE column1 = ANY (SELECT column1 FROM t2); 

•Incorrectly used table in subquery: 

